Dynamic "Deactivation" mechanism enables epoxides ring-opening to prepare α-substituted alcohols.

Abstract

The selective synthesis of α-substituted alcohols from epoxides remains challenging. A promising strategy involves Lewis acid (LA)-catalyzed Meinwald rearrangement of epoxides, followed by 1,2-addition to in situ-generated aldehydes. However, generalizing this approach is complicated by a mechanistic contradiction: LAs promote the rearrangement but also facilitate side reactions of inherently enolizable aldehydes. Here, we show that NaI stabilizes these aldehydes by forming reversible α-oxy iodides, temporarily suppressing side reactions while maintaining their availability for Ni-catalyzed 1,2-arylation. This dynamic "deactivation" mechanism enables the synthesis of α-arylated alcohols from arylboronic acids and diverse epoxides, including previously elusive 2-alkyl variants. Extensive screening identifies a chiral bidentate nitrogen ligand that allows a rare asymmetric synthesis of α-substituted alcohols from racemic epoxides, in an enantioconvergent manner. Moreover, the method demonstrates broader applicability beyond using epoxides merely as bench-stable aliphatic aldehyde precursors, expanding their utility in alcohol synthesis.