Stereoselective Preparation and Palladium-Catalyzed Suzuki–Miyaura Cross-Coupling of Alkenyl Sulfoximines

Although numerous transition-metal catalyzed cross-coupling reactions of alkenyl electrophiles with a sulfur(VI) leaving group, mainly alkenyl sulfones, have been developed, most rely heavily on highly nucleophilic Grignard reagents, and the use of organoboron reagents remains challenging. We report herein facile preparation and the following Pd-catalyzed Suzuki–Miyaura cross-coupling reaction of alkenyl sulfoximine, a monoaza analog of sulfone. The condensation of alkyl sulfoximine with aldehydes, developed in this study, makes alkenyl sulfoximines more readily available. The resulting alkenes undergo an unprecedented oxidative addition of the C−S bond to the Pd center. This cross-coupling proceeds with retention of its original stereochemistry and provided alkenes bearing three different functionalities in a stereoselective fashion. DFT calculations highlight the critical role of boronic acid and in situ-generated boroxines in facilitating this transformation.