Nickel-Catalyzed Reaction of Iodofluoroacetates with Alkenes and Zinc: A Novel and Practical Route to α,α-Difluoro-Functionalized Esters and α,α,ω,ω-Tetrafluoro Diesters

Article abstract of DOI:10.1021/jo00045a027

Iododifluoroacetates 1a-c react with alkenes and zinc in the presence of nickel dichloride hexahydrate in THF at room temperature or 60 deg C to give the corresponding α,α-difluoro esters in good yields.The reaction is also applicable to alkenes containing a variety of functional groups such as trimethylsilyl, hydroxy, ketone, and ester moieties.The reaction of 1 works well with dienes; the products formed depend on the length of chain of the dienes. 1,8-Nonadiene and 1,5-hexadiene afford the α,α,ω,ω-tetrafluoro diesters, while 1,6-heptadiene gave a mixture of ethyl 2,2-difluoro-8-nonenoate (19) and the cyclopentyl-substituted α,α-difluoroester 20.When diallyl ether was used as a substrate, only the tetrahydrofuran derivative 21 was formed.The nickel-catalyzed reaction can be suppressed by p-dinitrobenzene and hydroquinone.A single electron transfer initiated radical mechanism is proposed.