Organocatalytic asymmetric α-benzoyloxylation of α-branched aldehydes and enals: a useful approach to oxygenated quaternary stereocenters

Direct asymmetric alpha-benzoyloxylation of alpha-branched aldehydes and alpha-branched enals via enamine and dienamine catalysis was used to construct quaternary oxygenated stereocenters with good yields and moderate to good enantioselectivity. This method uses an inexpensive and readily available cinchona alkaloid-derived primary amine as the catalyst, benzoyl peroxide as the oxygen source, and stoichiometric amounts of the aldehyde substrates, providing simple metal-free access to valuable protected 2-hydroxyaldehyde derivatives. (C) 2012 Published by Elsevier Ltd.