Sulfenofunctionalization of Chiral α-Trifluoromethyl Allylboronic Acids: Asymmetric Synthesis of SCF 3 , SCF 2 R, SCN and SAr Compounds.

We report herein a new method for the synthesis of densely functionalized chiral allyl SCF 3 , SCF 2 R, SCN and SAr species with a separate CF 3 functionality. The synthetic approach is based on selenium-catalyzed sulfenofunctionalization of chiral α-CF 3 allylboronic acids. The reactions proceeded with remarkably high stereo-, diastereo- and site-selectivity, based on the formation of a stable thiiranium ion followed by rapid deborylative ring opening.