One-pot three-component catalytic enantioselective synthesis of homoallylboronates

Abstract

No longer a simple bor(ation): The title reaction between bis(pinacolato)diboron, enals, and 2-(triphenylphosphoranylidene)acetates employing bench-stable copper salts and a simple chiral amine co-catalyst is presented (see scheme). The reaction proceeds through a catalytic asymmetric conjugate borane addition/Wittig sequence wherein the β-boration step is 1,4-selective and gives the corresponding homoallylboronate products with high enantiomeric ratios. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.