Oxidation of catecholboron enolates with tempo

Abstract

Persistent radical meets enolates: Catecholboron ketone enolates are oxidized efficiently under mild conditions by treatment with the persistent TEMPO radical. Catecholboron enolates are readily prepared by 1,4- reduction of α, β-unsaturated ketones or by transmetalation of silyl enol ethers and zinc enolates with chlorocatecholboranes. Enolate formation and oxidation can be performed as a one-pot process with high regioand stereoselectivity. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.