Reagent-controlled asymmetric homologation of boronic esters by enantioenriched main-group chiral carbenoids.
[reaction: see text] Putative enantioenriched carbenoid species, (R)-1-chloro-2-phenylethylmagnesium chloride (9) and (S)-1-chloro-2-phenylethyllithium (26), generated in situ by sulfoxide ligand exchange from (-)-(R(S),R)-1-chloro-2-phenylethyl p-tolyl sulfoxide (8), effected the stereocontrolled homologation of boronic esters. sec-Alcohols derived from the product boronates by oxidation with basic hydrogen peroxide exhibited % ee closely approaching that of sulfoxide 8 in examples employing Li-carbenoid 26.
Department of Chemisty, Oregon State University, Corvallis, Oregon, 97331-4003, USA. paul.blakemore@science.oregonstate.edu
Paul R
PR
Blakemore
Stephen P
SP
Marsden
Huw D
HD
Vater