Precatalyst-Enabled Selectivity: Enantioselective NiH-catalyzed anti-Hydrometalative Cyclization of Alkynones to endo- and Hetero-cyclic Allylic Alcohols

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 enantio-selectivity. 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.