Asymmetric 1,4-hydrosilylations of alpha,beta-unsaturated esters.

ABSTRACT

Complexing catalytic amounts of CuH with a nonracemic JOSIPHOS or SEGPHOS ligand, together with stoichiometric PMHS, leads to exceedingly efficient and highly enantioselective 1,4-reductions of beta,beta-disubstituted enoates and lactones. An unprecedented substrate-to-ligand ratio of 77001 for this type of reaction is documented.