A novel method for the synthesis of 2,2-diaryl-1,1-difluoroethenes
作者:Ji Hoon Choi、In Howa Jeong
DOI:10.1016/j.tetlet.2007.12.028
日期:2008.2
β,β-Difluoro-α-phenylvinylstannane 3 was prepared in 60% yield from the reaction of β,β-difluoro-α-phenylvinylsulfone 2 with tributyltin hydride in refluxing benzene for 5 h. The cross-coupling reaction of 3 with aryl iodides bearing substituents such as proton, fluoro, chloro, bromo, methoxy, methyl, trifluoromethyl, and nitro on ortho, meta, para positions of the benzene ring in the presence of 10 mol %
achieved in high yields via the reaction with difluorocarbene. When aryl or alkyl dithiocarboxylates were treated with trimethylsilyl 2,2-difluoro-2-fluorosulfonylacetate in the presence of 5 mol % of a Proton Sponge catalyst, the in situ generated difluorocarbene reacted with the dithioesters to afford 2-sulfanylated 1,1-difluoro-1-alkenes via difluorothiiranes. This reaction can be considered as an electrophilic
Radical Addition Reactions of α-Substituted β,β-Difluorovinyl Sulfones
作者:In Howa Jeong、Sung Lan Jeon、Bum Tae Kim
DOI:10.1080/00397910008087053
日期:2000.12
Abstract The radical addition reactions of α-substituted β,β-difluorovinyl sulfones 1 with α-oxy and acyl radical species, such as 1,3-dioxolane, tetrahydrofuran, 1,4-dioxane, butanal and hexanal, afforded radical addition products 2--16 in good yields.
reaction described herein is an electrophilic counterpart to the Wittig-type (nucleophilic) difluoroalkene synthesis starting from carbonyl compounds. The electrophilic difluoromethylidenation facilitated the synthesis of sulfanylated and diarylated 1,1-difluoroalkenes, including stericallyhindered ones, which are inaccessible by nucleophilic difluoromethylidenation.