An efficient room temperature preparation of bromo difluorovinylzinc reagent (CF2=CBrZnCl) and a high yield one-pot synthesis of cz-bromo-β,β-difluorostyrenes

A high yield room temperature preparation of the 1-bromo-2,2-difluorovinylzinc reagent [CF2=CBrZnCl] (>89%) was achieved via insitu metallation of CF3CH2Br or CF2=CHBr with LDA in presence of ZnCl2. Palladium catalyzed cross-coupling of this zinc reagent with aryl iodides provides alpha-bromo-beta,beta-trifluorostyrenes (ArCBr=CF2) in 64-86% isolated yields, in an essentially 'one-pot' procedure. (C) 2004 Elsevier B.V. All rights reserved.