Cr-Catalyzed Diastereo- and Enantioselective Synthesis of β-Hydroxy Sulfides and Selenides

The Cr-catalyzed Nozaki–Hiyama–Kishi reaction serves as a reliable and valuable C–C bond construction strategy in organic synthesis. However, known Cr-catalyzed asymmetric transformations are limited mainly to primary Cr intermediates with an α-substituted π-functional group, which impeded their further synthetic applications. Herein, we described a Cr-catalyzed three-component reaction, which provides modular access to valuable chiral β-hydroxy sulfides and selenides with vicinal stereocenters. Based on preliminary mechanistic studies, this method proceeds via the asymmetric reductive radical-polar crossover, featuring unprecedented secondary chiral alkyl Cr complex stabilized by the α-sulfur or selenium.