Precatalyst‐Enabled Selectivity: Enantioselective NiH‐Catalyzed <i>anti</i>‐Hydrometalative Cyclization of Alkynones to <i>Endo</i>‐ and Heterocyclic Allylic Alcohols
Xiaowen Zhang, Minghui Zhu, Hai‐Xiang Zeng, Qi‐Yang Li, Wen‐Bo Liu
Abstract
Abstract A highly enantioselective NiH‐catalyzed hydrocyclization of alkynones with unparalleled anti ‐ and endocyclic selectivities is described. The choice of the precatalysts has significant influence in tuning the regio‐ and enantioselectivity. Using Ni(OTs) 2 /Phox as a precatalyst and (EtO) 2 MeSiH as a hydride source, an array of enantioenriched O‐, N‐, and S‐containing heterocyclic tertiary allylic alcohols are obtained in 24–81 % yields with 80:20–99:1 er. Mechanistic investigations and synthetic application are also carried out. This study represents an efficient access to a set of allylic alcohols that are unable to access by the state‐of‐the‐art coupling reactions.