Rh(I)/Bisoxazolinephosphine-Catalyzed Regio- and Enantioselective Allylic Substitutions

Rhodium­(I)/bisoxazolinephosphine
combination has been developed
as a general catalyst to achieve the dynamic kinetic asymmetric allylation
of a variety of nitrogen, carbon, oxygen, and sulfur pronucleophiles
from branched racemic allylic carbonates. Exclusive branch-selectivity
and up to 99% enantiomeric excess could be obtained under neutral
conditions. Linear allylic substrates (both Z and E) could be converted to the same chiral branched products
with excellent regio- and enantioselectivities as well. Chiral π-allyl-Rh­(III)/NPN
intermediate was isolated and characterized to understand the origin
of the high selectivities.