α-C−H Alkylation of α-Silyl Alcohols: Hydrogen Atom Transfer Catalysis Preserving Labile C−Si Bonds

Abstract α-Silyl alcohols are organosilicon motifs that serve as precursors to carbanions and carbon-centered radicals for the construction of silicon-containing molecules and complex carbon frameworks. Despite their synthetic utility, facile methods for preparing structurally diverse α-silyl alcohols remain underdeveloped. Herein, we report a photocatalytic strategy for upgrading readily available, structurally simple α-silyl alcohols into functionalized derivatives via hydrogen atom transfer (HAT) catalysis. The use of phosphonium ylide as a highly tunable HAT catalyst, in combination with a visible-light photoredox catalyst, enables selective α-C−H alkylation without cleavage of the labile C−Si bond, providing access to diverse α-silyl alcohols with good functional group compatibility. Furthermore, orthogonal transformations of the C−H, C−O, and C−Si bonds in α-silyl alcohols demonstrate their utility as versatile building blocks.