Nature Research Acta Medica Okayama 2399-3669 4 1 2021 Halogen-sodium exchange enables efficient access to organosodium compounds 76 EN Sobi Asako Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University Ikko Takahashi RIKEN Center for Sustainable Resource Science Hirotaka Nakajima Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University Laurean Ilies RIKEN Center for Sustainable Resource Science Kazuhiko Takai Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University With sodium being the most abundant alkali metal on Earth, organosodium compounds are an attractive choice for sustainable chemical synthesis. However, organosodium compounds are rarely used-and are overshadowed by organolithium compounds-because of a lack of convenient and efficient preparation methods. Here we report a halogen-sodium exchange method to prepare a large variety of (hetero)aryl- and alkenylsodium compounds including tri- and tetrasodioarenes, many of them previously inaccessible by other methods. The key discovery is the use of a primary and bulky alkylsodium lacking beta-hydrogens, which retards undesired reactions, such as Wurtz-Fittig coupling and beta-hydrogen elimination, and enables efficient halogen-sodium exchange. The alkylsodium is readily prepared in situ from neopentyl chloride and an easy-to-handle sodium dispersion. We believe that the efficiency, generality, and convenience of the present method will contribute to the widespread use of organosodium in organic synthesis, ultimately contributing to the development of sustainable organic synthesis by rivalling the currently dominant organolithium reagents. Halogen-sodium exchange reactions with neopentyl sodium provides access to a range of aryl and alkenyl organosodium compounds in situ, as an alternative to organolithium reagents. No potential conflict of interest relevant to this article was reported.

American Chemical Society Acta Medica Okayama 00027863 141 25 2019 Deoxygenative Insertion of Carbonyl Carbon into a C(sp3)–H Bond: Synthesis of Indolines and Indoles 9832 9836 EN Sobi Asako Graduate School of Natural Science and Technology, Okayama University Seina Ishihara Graduate School of Natural Science and Technology, Okayama University Keiya Hirata Graduate School of Natural Science and Technology, Okayama University Kazuhiko Takai Graduate School of Natural Science and Technology, Okayama University A simple deoxygenation reagent prepared in situ from commercially available Mo(CO)6 and ortho-quinone has been developed for the synthesis of indoline and indole derivatives. The Mo/quinone complex efficiently deoxygenates carbonyl compounds bearing a neighboring dialkylamino group and effects intramolecular cyclizations with the insertion of a deoxygenated carbonyl carbon into a C(sp3)–H bond, in which a carbonyl group acts as a carbene equivalent. The reaction also proceeds with a catalytic amount of Mo/quinone in the presence of disilane as an oxygen atom acceptor. No potential conflict of interest relevant to this article was reported.

American Chemical Society Acta Medica Okayama 00027863 140 45 2018 Use of Cyclopropane as C1 Synthetic Unit by Directed Retro- Cyclopropanation with Ethylene Release 15425 15429 EN Asako Sobi Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University Takaaki Kobashi Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University Kazuhiko Takai Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University Cyclopropanation of alkenes is a well-established textbook reaction for the synthesis of cyclopropanes, where a ghigh-energyh carbene species is exploited to drive the reaction forward. However, little attention has been focused toward molecular transformations involving the reverse reaction, retro-cyclopropanation (RC). This is because of difficulties associated with both cleaving the two geminal C–C single bonds and exploiting the generated carbenes for further transformations in an efficient and selective manner. Here, we report that a molybdenum-based catalytic system overcomes the above challenges and effects the RC of cyclopropanes bearing a pyridyl group with the release of ethylene (alkene) and the subsequent intramolecular cyclization leading to pyrido[2,1-a]isoindoles. The reaction allows for the uncommon use of cyclopropanes as C1 synthetic units in contrast to most conventional reactions in which cyclopropanes are used as C3 synthetic units. We anticipate that this new strategy will pave the way for C1 cyclopropane chemistry. No potential conflict of interest relevant to this article was reported.