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 alpha-halo-beta,beta-difluorostyrenes.
[reaction: see text] Alpha-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.
Raghavanpillai
Anilkumar
A
Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA.
Burton
Donald J
DJ
D000475:Alkenes / Q000138:chemical synthesis / Q000737:chemistry*; D000478:Alkylation; D001897:Boronic Acids / Q000737:chemistry; D001966:Bromine / Q000737:chemistry; D005461:Fluorine / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry; D015394:Molecular Structure; D013343:Styrenes / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
D000475:Alkenes; D001897:Boronic Acids; D006219:Halogens; D013343:Styrenes; D005461:Fluorine; D015032:Zinc; D001966:Bromine