Abstract

Vinyl boronates represent a class of versatile building blocks in organic synthesis.1 They can be easily transformed into other useful molecules, for example, by cross-coupling and functional group interconversion. Hydroboration of alkynes, represents one of the most straightforward approaches for the synthesis of vinyl boronates with high regioselectivity and stereoselectivity. Thioalkynes can potentially undergo regioselective hydroboration to form sulfur-substituted vinyl boronates. Herein, we have developed an alternative approach to α-borylation of thioalkynes catalyzed by [(cod)Ir(OMe)]2 with HBpin (pinacolborane) under mild conditions. Excellent α-regioselectivity was achieved to deliver only Z-vinylboronates. Furthermore, double hydroboration could also be obtained with the same catalytic system, a new process with high efficiency and regioselectivity. Details will be presented in due course. 

Reference:

1. Mkhalid, I. A. I.; Barnard, J. H.; Marder, T. B.; Murphy, J. M.; Hartwig., J. F. Chem. Rev. 2010, 110, 890.