Difluoroallenyl bromide as a wide-ranging difluoromethylene cation equivalent: SN2 substitution of difluoropropargyl bromide through sequential SE2′ and SN2′ reactions

Abstract

(Chemical Equation Presented) A synthetic challenge: a two-step conversion of RCF2Br into RCF2Nu has been achieved (see scheme; Nu = nucleophile). Nucleophilic substitution at a difluoromethylene carbon atom is carried out by using a functionalized difluoroallene as a CF2 cation equivalent. The resulting product contains a triisopropylsilyl (TIPS) - acetylenic linkage suitable for further functionalization. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.