New Efficient Approach to 2,2-Diaryl-1,1-difluoro-1-alkenes and 1,1-Difluoro-2-aryl-1,3-dienes via Suzuki Coupling of α-Halo-β,β-difluorostyrenes
摘要:
[Graphics]a-Halo-beta,beta-difluorostyrenes [ArCX = CF2; X = Br, I; Ar = aryl, heteroaryl; synthesized by the Pd(0)-catalyzed coupling reaction of the corresponding alpha-halo-beta,beta-difluoroethenylzinc reagents (CF2=CXZnCl, X = Br, I) with aryl iodides] were functionalized at the halogen site with arylboronic acids under Pd(0)-catalyzed Suzuki-Miyaura coupling reaction conditions to obtain 2,2-diaryl-1,1-difluoro-1-alkenes (ArAr'C=CF2, Ar' = aryl, heteroaryl) in 51-91% isolated yield. The corresponding reaction with alkenylboronic acids produced 1,1-difluoro-2-aryl-1,3-dienes in 53-80% isolated yield. Alternatively, 2,2-disubstituted-1,1-difluoro-1-alkenes were synthesized in moderate yield by a zinc-insertion reaction at the halogen site of the alpha-halo-beta,beta-difluorostyrenes, followed by Pd(0)-catalyzed cross-coupling of the zinc reagent with aryl or alkenyl iodides.
Facile synthesis of unsymmetrical 1,1-diaryl-2,2-difluoroethenes via stepwise coupling of 1,1-dibromo-2,2-difluoroethenes
摘要:
Unsymmetrical 1,1-diaryl-2,2-difluoroethenes were synthesized from 1,1-dibromo-2,2-difluoroethene, which is commercially available, via the Suzuki-Miyaura coupling in a stepwise fashion. Suitable ligands for each coupling process were used to achieve selective synthesis of these diaryldifluoroethenes. (C) 2013 Elsevier B.V. All rights reserved.
An efficient room temperature preparation of bromo difluorovinylzinc reagent (CF2CBrZnCl) and a high yield one-pot synthesis of α-bromo-β,β-difluorostyrenes
作者:R. Anilkumar、Donald J. Burton
DOI:10.1016/j.jfluchem.2003.11.029
日期:2004.4
A high yield room temperature preparation of the1-bromo-2,2-difluorovinylzinc reagent [CF2CBrZnCl] (>89%) was achieved via insitu metallation of CF3CH2Br or CF2CHBr with LDA in presence of ZnCl2. Palladium catalyzed cross-coupling of this zinc reagent with aryl iodides provides α-bromo-β,β-trifluorostyrenes (ArCBrCF2) in 64–86% isolated yields, in an essentially ‘one-pot’ procedure.