start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=e202403213 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250218 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Antifouling Activity of Xylemin, Its Structural Analogs, and Related Polyamines en-subtitle= kn-subtitle= en-abstract= kn-abstract=Biofouling, which is the accumulation of organisms on undersea structures, poses significant global, social, and economic issues. Although organotin compounds were effective antifoulants since the 1960s, they were banned in 2008 due to their toxicity to marine life. Although tin-free alternatives have been developed, they also raise environmental concerns. This underscores the need for effective, nontoxic antifouling agents. We previously synthesized N-(4-aminobutyl)propylamine (xylemin) and its structural analogs. In this study, we assayed the antifouling activity and toxicity of xylemin, its structural analogs, and related polyamines toward cypris larvae of the barnacle Amphibalanus amphitrite. Xylemin and its Boc-protected analog exhibited antifouling activities with 50% effective concentrations (EC50) of 4.25 and 6.11 ?g/mL, respectively. Four xylemin analogs did not show a settlement-inhibitory effect at a concentration of 50 ?g/mL. Putrescine, spermidine, spermine, and thermospermine, which are xylemin-related polyamines, did not display antifoulant effects (EC50 > 50 ?g/mL). All evaluated compounds were nontoxic at a concentration of 50 ?g/mL. These findings indicate that the size and structure of the N-alkyl group are essential for the antifouling activity of xylemin. Therefore, xylemin and its analogs hold promise as nontoxic, eco-friendly antifouling agents, offering a sustainable solution to biofouling in marine environments. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YorisueTakefumi en-aut-sei=Yorisue en-aut-mei=Takefumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TanakaKenta en-aut-sei=Tanaka en-aut-mei=Kenta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Institute of Natural and Environmental Sciences, University of Hyogo kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=4 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Amines kn-keyword=Amines en-keyword=Antifouling activity kn-keyword=Antifouling activity en-keyword=Barnacle kn-keyword=Barnacle en-keyword=Structure?activity relationships kn-keyword=Structure?activity relationships en-keyword=Xylemin kn-keyword=Xylemin END start-ver=1.4 cd-journal=joma no-vol=22 cd-vols= no-issue=28 article-no= start-page=5739 end-page=5747 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=2024 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Total synthesis and structure?antifouling activity relationship of scabrolide F en-subtitle= kn-subtitle= en-abstract= kn-abstract=An efficient synthetic strategy for scabrolide F (7), a norcembranolide diterpene that was isolated from the Taiwanese soft coral Sinularia scabra, has only recently been reported by our group. Herein, we report details of the first total synthesis of 7. The tetrahydrofuran domain of 7 was stereoselectively constructed via the 5-endo-tet cyclization of a hydroxy vinyl epoxide. The reaction of alkyl iodide 30 with dithiane 38, followed by the introduction of an alkene moiety, afforded allylation precursor 41. The coupling of alkyl iodide 42 and allylic stannane 43 was examined as a model experiment of allylation. Because the desired allylated product 44 was not obtained, an alternative synthetic route toward 7 was investigated instead. In the second synthetic approach, fragment?coupling between alkyl iodide 56 and aldehyde 58, macrolactonization, and transannular ring-closing metathesis were used as the key steps to achieve the first total synthesis of 7. We hope that this synthetic strategy provides access to the total synthesis of other macrocyclic norcembranolides. We also evaluated the antifouling activity and toxicity of 7 and its synthetic intermediates toward the cypris larvae of the barnacle Amphibalanus amphitrite. This study is the first to report the antifouling activity of norcembranolides as well as the biological activity of 7. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SugitaniYuki en-aut-sei=Sugitani en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MorishitaRyohei en-aut-sei=Morishita en-aut-mei=Ryohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YorisueTakefumi en-aut-sei=Yorisue en-aut-mei=Takefumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Institute of Natural and Environmental Sciences, University of Hyogo kn-affil= affil-num=5 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230929 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Relative stereochemical determination of the C61?C83 fragment of symbiodinolide using a stereodivergent synthetic approach en-subtitle= kn-subtitle= en-abstract= kn-abstract=Structural determination is required in the use of marine natural products to create novel drugs and drug leads in medicinal chemistry. Symbiodinolide, which is a polyol marine natural product with a molecular weight of 2860, increases the intracellular Ca2+ concentration and exhibits inhibitory activity against cyclooxygenase-1. Seventy percent of the structure of symbiodinolide has been stereochemically clarified. Herein, we report the elucidation of the relative configuration of the C61?C83 fragment, which is among the remaining thirty percent, using a stereodivergent synthetic strategy. We first assigned the relative configuration of the C61?C74 fragment. Two candidate diastereomers of the C61?C74 fragment were synthesized, and their NMR data were compared with those of the natural product, revealing the relative stereochemistry of this component. We then narrowed down the candidate compounds for the C69?C83 fragment from 16 possible diastereomers by analyzing the NMR data of the natural product, and we thus selected eight candidate diastereomers. Stereodivergent synthesis of the candidates for this fragment and comparison of the NMR data of the natural product and the eight synthetic products resulted in the relative stereostructural clarification of the C69?C83 fragment. These individually determined relative stereochemistries of the C61?C74 and C69?C83 fragments were connected via the common C69?C73 tetrahydropyran moiety of the fragments. Finally, the relative configuration of the C61?C83 fragment of symbiodinolide was determined. The stereodivergent synthetic approach used in this study can be extended to the stereochemical determination of other fragments of symbiodinolide. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HattoriKosuke en-aut-sei=Hattori en-aut-mei=Kosuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=OhashiTakumi en-aut-sei=Ohashi en-aut-mei=Takumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=OtsuTaichi en-aut-sei=Otsu en-aut-mei=Taichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=21 cd-vols= no-issue=3 article-no= start-page=632 end-page=638 dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20221220 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Chemical synthesis and antifouling activity of monoterpene?furan hybrid molecules en-subtitle= kn-subtitle= en-abstract= kn-abstract=Geraniol, a monoterpene, and furan are structural motifs that exhibit antifouling activity. In this study, monoterpene-furan hybrid molecules with potentially enhanced antifouling activity were designed and synthesized. The nine synthetic hybrids showed antifouling activity against the cypris larvae of the barnacle Balanus (Amphibalanus) amphitrite with EC50 values of 1.65-4.70 mu g mL(-1). This activity is higher than that of geraniol and the reference furan compound. This hybridization approach to increase antifouling activity is useful and can also be extended to other active structural units. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KinoshitaYuya en-aut-sei=Kinoshita en-aut-mei=Yuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YorisueTakefumi en-aut-sei=Yorisue en-aut-mei=Takefumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Institute of Natural and Environmental Sciences, University of Hyogo kn-affil= affil-num=4 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=24 cd-vols= no-issue=42 article-no= start-page=7845 end-page=7849 dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20221020 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Total Synthesis of Scabrolide F en-subtitle= kn-subtitle= en-abstract= kn-abstract=The first total synthesis of scabrolide F, a norcembranolide isolated from the soft coral Sinularia scabra, is described. Hydroxycarboxylic acid, which is the key synthetic intermediate, was synthesized in a convergent manner by fragment coupling. The obtained hydroxycarboxylic acid was subjected to macrolactonization and subsequent transannular ring-closing metathesis (RCM) to furnish scabrolide F. The synthetic protocol can be extended to the total synthesis of other norcembranolides. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SugitaniYuki en-aut-sei=Sugitani en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MorishitaRyohei en-aut-sei=Morishita en-aut-mei=Ryohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=2020 cd-vols= no-issue=18 article-no= start-page=2745 end-page=2753 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200320 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Chemical Synthesis and Biological Effect on Xylem Formation of Xylemin and Its Analogues en-subtitle= kn-subtitle= en-abstract= kn-abstract=Xylemin (6 ) and its designed structural analogues 18 ?23 , N ](4]aminobutyl)alkylamines, were synthesized by 2]nitrobenzenesulfonamide (Ns) strategy. Investigation of the improved synthesis of 20 ?23 resulted in the development of one]step synthesis of these analogues from the commercially available corresponding ketones. Biological assessment of the synthetic molecules elucidated that xylemin (6 ) and the analogue N ](4]aminobutyl)cyclopentylamine (21 ) promoted the expression level of thermospermine synthase ACAULIS5 (ACL5 ) and enhanced xylem formation. In addition, xylemin (6 ) was found to significantly promote lateral root formation, whereas xylemin analogues 18 ?23 including 21 did not. These results indicate that the analogue 21 has the potential as a novel inhibitor of thermospermine synthesis to work specifically in xylem differentiation. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MotoseHiroyasu en-aut-sei=Motose en-aut-mei=Hiroyasu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=OtsuTaichi en-aut-sei=Otsu en-aut-mei=Taichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ShinoharaShiori en-aut-sei=Shinohara en-aut-mei=Shiori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KounoRyugo en-aut-sei=Kouno en-aut-mei=Ryugo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=TakahashiTaku en-aut-sei=Takahashi en-aut-mei=Taku kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Amines kn-keyword=Amines en-keyword=Biological activity kn-keyword=Biological activity en-keyword=Chemical synthesis kn-keyword=Chemical synthesis en-keyword=Reductive amination kn-keyword=Reductive amination en-keyword=Structure]activity relationships kn-keyword=Structure]activity relationships END start-ver=1.4 cd-journal=joma no-vol=83 cd-vols= no-issue=18 article-no= start-page=11028 end-page=11056 dt-received= dt-revised= dt-accepted= dt-pub-year=2018 dt-pub=20180809 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Unified Total Synthesis, Stereostructural Elucidation, and Biological Evaluation of Sarcophytonolides en-subtitle= kn-subtitle= en-abstract= kn-abstract= Sarcophytonolides are cembranolide diterpenes isolated from the soft corals of genus Sarcophyton. Unified total synthesis of sarcophytonolides C, E, F, G, H, and J and isosarcophytonolide D was achieved. The synthetic routes feature NaHMDS- or SmI2-mediated fragment coupling, alkoxycarbonylallylation, macrolactonization, and transannular ring-closing metathesis. These total syntheses led to the absolute configurational confirmation of sarcophytonolide H, elucidation of sarcophytonolides C, E, F, and G, and revision of sarcophytonolide J and isosarcophytonolide D. We also evaluated the antifouling activity and toxicity of the synthetic sarcophytonolides H and J and their analogues as well as the cytotoxicity of the synthetic sarcophytonolides and the key synthetic intermediates. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KikuchiTakahiro en-aut-sei=Kikuchi en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=IwamotoKohei en-aut-sei=Iwamoto en-aut-mei=Kohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NakaoEiji en-aut-sei=Nakao en-aut-mei=Eiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HaradaNaoki en-aut-sei=Harada en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=OtsuTaichi en-aut-sei=Otsu en-aut-mei=Taichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=EndoNoriyuki en-aut-sei=Endo en-aut-mei=Noriyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=FukudaYuji en-aut-sei=Fukuda en-aut-mei=Yuji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=OhnoOsamu en-aut-sei=Ohno en-aut-mei=Osamu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=SuenagaKiyotake en-aut-sei=Suenaga en-aut-mei=Kiyotake kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=GuoYue-Wei en-aut-sei=Guo en-aut-mei=Yue-Wei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology , Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology , Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology , Okayama University kn-affil= affil-num=4 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology , Okayama University kn-affil= affil-num=5 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology , Okayama University kn-affil= affil-num=6 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology , Okayama University kn-affil= affil-num=7 en-affil=Himeji EcoTech Co., Ltd. kn-affil= affil-num=8 en-affil=Himeji EcoTech Co., Ltd. kn-affil= affil-num=9 en-affil= Department of Chemistry and Life Science, School of Advanced Engineering , Kogakuin University kn-affil= affil-num=10 en-affil= Department of Chemistry, Faculty of Science and Technology , Keio University kn-affil= affil-num=11 en-affil=Shanghai Institute of Materia Medica , Chinese Academy of Sciences kn-affil= affil-num=12 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology , Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=59 cd-vols= no-issue=11 article-no= start-page=955 end-page=966 dt-received= dt-revised= dt-accepted= dt-pub-year=2018 dt-pub=20180210 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Recent topics of the stereodivergent synthesis of natural products en-subtitle= kn-subtitle= en-abstract= kn-abstract= A variety of natural products, a valuable source of drug lead compounds, coexist with their stereoisomers as congeners. For pursuing the structural elucidation and the structure?activity relationship study of natural products, it is needed to establish the streamlined synthetic route to supply natural products and their stereoisomers. Divergent pathway is one of the synthetic strategies to deliver more than one target compound. In this digest, selected examples of the stereodivergent approach toward the synthesis of natural products are described. Especially, this digest focuses on common synthetic intermediates and stereodiversification steps from the common intermediates to reach the target compounds. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Natural product kn-keyword=Natural product en-keyword=Stereodivergent synthesis kn-keyword=Stereodivergent synthesis en-keyword=Stereodiversification kn-keyword=Stereodiversification en-keyword=Stereoisomer kn-keyword=Stereoisomer END start-ver=1.4 cd-journal=joma no-vol=80 cd-vols= no-issue=6 article-no= start-page=3111 end-page=3123 dt-received= dt-revised= dt-accepted= dt-pub-year=2015 dt-pub=20150227 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Stereodivergent synthesis and relative stereostructure of the C1-C13 fragment of symbiodinolide en-subtitle= kn-subtitle= en-abstract= kn-abstract= Four possible diastereomers of the C1-C13 fragment of symbiodinolide, which were proposed by the stereostructural analysis of the degraded product, were synthesized in a stereodivergent and stereoselective manner. The key transformations were aldol reaction of methyl acetoacetate with the aldehyde, diastereoselective reduction of the resulting -hydroxy ketone, and the stereoinversion at the C6 position. Comparison of the (1)H NMR data between the four synthetic products and the degraded product revealed the relative stereostructure of the C1-C13 fragment of symbiodinolide. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=WadaHiroko en-aut-sei=Wada en-aut-mei=Hiroko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=OginoMao en-aut-sei=Ogino en-aut-mei=Mao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KikuchiTakahiro en-aut-sei=Kikuchi en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=UemuraDaisuke en-aut-sei=Uemura en-aut-mei=Daisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Chemistry, Faculty of Science, Kanagawa University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=22 cd-vols= no-issue=6 article-no= start-page=1984 end-page=1996 dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=201602 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Stereodivergent Synthesis and Stereochemical Reassignment of the C79-C104 Fragment of Symbiodinolide en-subtitle= kn-subtitle= en-abstract= kn-abstract= We have synthesized eight possible diastereoisomers 3?a-h of the C79-C97 fragment of symbiodinolide (1) in a stereodivergent manner by utilizing a dithiane addition to the aldehyde as a key step. Comparison of the 13 C?NMR chemical shifts of the natural product 1 and the synthetic products 3?a-h indicated that the relative stereostructure of this fragment in symbiodinolide (1) is that represented in 3?a or f. We have stereodivergently synthesized eight possible diastereoisomers of the C94-C104 fragment 4?a-h, and we have compared their 13 C?NMR chemical shifts with those of the natural product, which established the relative stereochemistry of this fragment to be that described in diastereoisomers 4?a or e. By combining the stereostructural outcomes of the C79-C97 and C94-C104 fragments, we have proposed four candidate compounds of the C79-C104 fragment 2?a-d. We also synthesized diastereoisomers 2?a and b (2?a in the preceding article; Chem. Eur. J. 2015, DOI: 10.1002/chem.201503880) by a Julia-Kocienski olefination and diastereoisomers 2?c and d by a Wittig reaction. By comparing the 13 C?NMR chemical shifts of natural symbiodinolide (1) with those of the synthetic products 2?a-d, we have reassigned the stereostructure of the C79-C104 fragment of natural product 1 to be that depicted in diastereoisomer 2?b. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FujiwaraTakayuki en-aut-sei=Fujiwara en-aut-mei=Takayuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawakuboYohei en-aut-sei=Kawakubo en-aut-mei=Yohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=UemuraDaisuke en-aut-sei=Uemura en-aut-mei=Daisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Chemistry, Faculty of Science, Kanagawa University kn-affil= en-keyword=macrocycles kn-keyword=macrocycles en-keyword=natural products kn-keyword=natural products en-keyword=polyols kn-keyword=polyols en-keyword=stereodivergent synthesis kn-keyword=stereodivergent synthesis en-keyword=structure elucidation kn-keyword=structure elucidation END start-ver=1.4 cd-journal=joma no-vol=22 cd-vols= no-issue=6 article-no= start-page=1979 end-page=1983 dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=201602 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Stereoselective Synthesis of the Proposed C79-C104 Fragment of Symbiodinolide en-subtitle= kn-subtitle= en-abstract= kn-abstract= Stereoselective and streamlined synthesis of the proposed C79-C104 fragment 2 of symbiodinolide (1), a polyol marine natural product with a molecular weight of 2860, was achieved. In the synthetic route, the proposed C79-C104 fragment 2 was synthesized by utilizing a Julia-Kocienski olefination and subsequent Sharpless asymmetric dihydroxylation as key transformations in a convergent manner. Detailed comparison of the 13 C?NMR chemical shifts between the natural product and the synthetic C79-C104 fragment 2 revealed that the stereostructure at the C91-C99 carbon chain moiety of symbiodinolide (1) should be reinvestigated. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FujiwaraTakayuki en-aut-sei=Fujiwara en-aut-mei=Takayuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawakuboYohei en-aut-sei=Kawakubo en-aut-mei=Yohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=UemuraDaisuke en-aut-sei=Uemura en-aut-mei=Daisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Chemistry, Faculty of Science, Kanagawa University kn-affil= en-keyword=macrocycles kn-keyword=macrocycles en-keyword=natural products kn-keyword=natural products en-keyword=polyols kn-keyword=polyols en-keyword=stereoselective synthesis kn-keyword=stereoselective synthesis en-keyword=structure elucidation kn-keyword=structure elucidation END start-ver=1.4 cd-journal=joma no-vol=18 cd-vols= no-issue=9 article-no= start-page=2110 end-page=2113 dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=20160506 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Total Synthesis of Sarcophytonolide H and Isosarcophytonolide D: Structural Revision of Isosarcophytonolide D and Structure-Antifouling Activity Relationship of Sarcophytonolide H en-subtitle= kn-subtitle= en-abstract= kn-abstract= The first total syntheses of sarcophytonolide H and the originally proposed and correct structures of isosarcophytonolide D have been achieved via transannular ring-closing metathesis (RCM). These total syntheses culminated in the stereostructural confirmation of sarcophytonolide H and the reassignment of isosarcophytonolide D, respectively. The antifouling activity of the synthetic sarcophytonolide H and its analogues was also evaluated. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KikuchiTakahiro en-aut-sei=Kikuchi en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=EndoNoriyuki en-aut-sei=Endo en-aut-mei=Noriyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FukudaYuji en-aut-sei=Fukuda en-aut-mei=Yuji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Himeji EcoTech Co., Ltd. kn-affil= affil-num=4 en-affil=Himeji EcoTech Co., Ltd. kn-affil= affil-num=5 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue=26 article-no= start-page=5549 end-page=5555 dt-received= dt-revised= dt-accepted= dt-pub-year=2017 dt-pub=20170613 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Late-stage divergent synthesis and antifouling activity of geraniol-butenolide hybrid molecules en-subtitle= kn-subtitle= en-abstract= kn-abstract= Hybrid molecules consisting of geraniol and butenolide were designed and synthesized by the late-stage divergent strategy. In the synthetic route, ring-closing metathesis was utilized for the construction of a butenolide moiety. A biological evaluation of the eight synthetic hybrid compounds revealed that these molecules exhibit antifouling activity against the cypris larvae of the barnacle Balanus (Amphibalanus) amphitrite with EC50 values of 0.30-1.31 g mL-1. These results show that hybridization of the geraniol and butenolide structural motifs resulted in the enhancement of the antifouling activity. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OhashiTakumi en-aut-sei=Ohashi en-aut-mei=Takumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KikuchiTakahiro en-aut-sei=Kikuchi en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=EndoNoriyuki en-aut-sei=Endo en-aut-mei=Noriyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=FukudaYuji en-aut-sei=Fukuda en-aut-mei=Yuji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Himeji EcoTech Co., Ltd. kn-affil= affil-num=5 en-affil=Himeji EcoTech Co., Ltd. kn-affil= affil-num=6 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=23 cd-vols= no-issue=68 article-no= start-page=17191 end-page=17194 dt-received= dt-revised= dt-accepted= dt-pub-year=2017 dt-pub=20171206 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Total Synthesis of Two Possible Diastereomers of Natural 6-Chlorotetrahydrofuran Acetogenin and Its Stereostructural Elucidation en-subtitle= kn-subtitle= en-abstract= kn-abstract= The first total synthesis of two possible diastereomers of natural 6-chlorotetrahydrofuran acetogenin 1 has been achieved. The synthetic route features 5-exo-tet cyclization, Z selective Wittig reaction and Julia olefination for the construction of conjugated diene and enyne moieties, and stereoselective chlorination. Comparison of their 1 H and 13 C?NMR data and specific rotation with those of the natural product elucidated the absolute configuration of natural (-)-6-chlorotetrahydrofuran acetogenin 1. en-copyright= kn-copyright= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KatsubeTomoya en-aut-sei=Katsube en-aut-mei=Tomoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=OkamotoKazuki en-aut-sei=Okamoto en-aut-mei=Kazuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil= Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=natural products kn-keyword=natural products en-keyword=stereoselective synthesis kn-keyword=stereoselective synthesis en-keyword=structure elucidation kn-keyword=structure elucidation en-keyword=tetrahydrofuran kn-keyword=tetrahydrofuran en-keyword=total synthesis kn-keyword=total synthesis END start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue= article-no= start-page=21487 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=20160216 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Chemical control of xylem differentiation by thermospermine, xylemin and auxin en-subtitle= kn-subtitle= en-abstract= kn-abstract= The xylem conducts water and minerals from the root to the shoot and provides mechanical strength to the plant body. The vascular precursor cells of the procambium differentiate to form continuous vascular strands, from which xylem and phloem cells are generated in the proper spatiotemporal pattern. Procambium formation and xylem differentiation are directed by auxin. In angiosperms, thermospermine, a structural isomer of spermine, suppresses xylem differentiation by limiting auxin signalling. However, the process of auxin-inducible xylem differentiation has not been fully elucidated and remains difficult to manipulate. Here, we found that an antagonist of spermidine can act as an inhibitor of thermospermine biosynthesis and results in excessive xylem differentiation, which is a phenocopy of a thermospermine-deficient mutant acaulis5 in Arabidopsis thaliana. We named this compound xylemin owing to its xylem-inducing effect. Application of a combination of xylemin and thermospermine to wild-type seedlings negates the effect of xylemin, whereas co-treatment with xylemin and a synthetic proauxin, which undergoes hydrolysis to release active auxin, has a synergistic inductive effect on xylem differentiation. Thus, xylemin may serve as a useful transformative chemical tool not only for the study of thermospermine function in various plant species but also for the control of xylem induction and woody biomass production. en-copyright= kn-copyright= en-aut-name=YoshimotoKaori en-aut-sei=Yoshimoto en-aut-mei=Kaori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MotoseHiroyasu en-aut-sei=Motose en-aut-mei=Hiroyasu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TakahashiTaku en-aut-sei=Takahashi en-aut-mei=Taku kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue= article-no= start-page=21487 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=20160216 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Chemical control of xylem differentiation by thermospermine, xylemin, and auxin en-subtitle= kn-subtitle= en-abstract= kn-abstract=The xylem conducts water and minerals from the root to the shoot and provides mechanical strength to the plant body. The vascular precursor cells of the procambium differentiate to form continuous vascular strands, from which xylem and phloem cells are generated in the proper spatiotemporal pattern. Procambium formation and xylem differentiation are directed by auxin. In angiosperms, thermospermine, a structural isomer of spermine, suppresses xylem differentiation by limiting auxin signalling. However, the process of auxin-inducible xylem differentiation has not been fully elucidated and remains difficult to manipulate. Here, we found that an antagonist of spermidine can act as an inhibitor of thermospermine biosynthesis and results in excessive xylem differentiation, which is a phenocopy of a thermospermine-deficient mutant acaulis5 in Arabidopsis thaliana. We named this compound xylemin owing to its xylem-inducing effect. Application of a combination of xylemin and thermospermine to wild-type seedlings negates the effect of xylemin, whereas co-treatment with xylemin and a synthetic proauxin, which undergoes hydrolysis to release active auxin, has a synergistic inductive effect on xylem differentiation. Thus, xylemin may serve as a useful transformative chemical tool not only for the study of thermospermine function in various plant species but also for the control of xylem induction and woody biomass production. en-copyright= kn-copyright= en-aut-name=YoshimotoKaori en-aut-sei=Yoshimoto en-aut-mei=Kaori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MotoseHiroyasu en-aut-sei=Motose en-aut-mei=Hiroyasu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TakahashiTaku en-aut-sei=Takahashi en-aut-mei=Taku kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=4 en-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil= kn-affil=Department of Biological Science, Graduate School of Natural Science and Technology, Okayama University END start-ver=1.4 cd-journal=joma no-vol=49 cd-vols= no-issue= article-no= start-page=3643 end-page=3647 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080619 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A cross-metathesis approach to the stereocontrolled synthesis of the AB ring segment of ciguatoxin en-subtitle= kn-subtitle= en-abstract= kn-abstract=

Synthesis of the AB ring segments of ciguatoxin is described. The present synthesis includes a Lewis acid mediated cyclization of allylstannane with aldehyde, cross-metathesis reaction introducing the side chain, and Grieco-Nishizawa dehydration on the A ring.

en-copyright= kn-copyright= en-aut-name=KadotaIsao en-aut-sei=Kadota en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AbeTakashi en-aut-sei=Abe en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UniMiyuki en-aut-sei=Uni en-aut-mei=Miyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TakamuraHiroyoshi en-aut-sei=Takamura en-aut-mei=Hiroyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YamamotoYoshinori en-aut-sei=Yamamoto en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Tohoku University affil-num=3 en-affil= kn-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=4 en-affil= kn-affil=Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University affil-num=5 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Tohoku University en-keyword=POLYCYCLIC ETHERS kn-keyword=POLYCYCLIC ETHERS en-keyword=ABSOLUTE-CONFIGURATION kn-keyword=ABSOLUTE-CONFIGURATION en-keyword=HYDROXY GROUP kn-keyword=HYDROXY GROUP en-keyword=MOIETY kn-keyword=MOIETY en-keyword=FRAGMENT kn-keyword=FRAGMENT en-keyword=SYSTEM kn-keyword=SYSTEM en-keyword=ROUTE kn-keyword=ROUTE en-keyword=CTX3C kn-keyword=CTX3C END