A silver‐mediated oxidative difluoromethylation of styrenes and vinyl trifluoroborates with TMSCF2H is reported for the first time. This method enables direct and facile access to CF2H‐alkenes from abundant alkenes with excellent functional‐group compatibility. Moreover, this Ag/TMSCF2H protocol could further enable a series of radical difluoromethylation reactions of a wide array of substrates, offering
Pd-Catalyzed Difluoromethylation of Vinyl Bromides, Triflates, Tosylates, and Nonaflates
作者:Dalu Chang、Yang Gu、Qilong Shen
DOI:10.1002/chem.201500551
日期:2015.4.13
Pd‐catalyzed difluoromethylation of di‐, tri‐ or tetra‐substituted vinyl bromides, triflates, tosylates and nonaflates under mild conditions is described. The reaction tolerates a wide range of functional groups, such as bromide, chloride, fluoride, ester, amine, nitrile, and protected carbonyl, thus providing a general route for the preparation of difluoromethylated alkenes.
Copper-Mediated Difluoromethylation of (Hetero)aryl Iodides and β-Styryl Halides with Tributyl(difluoromethyl)stannane
作者:G. K. Surya Prakash、Somesh K. Ganesh、John-Paul Jones、Aditya Kulkarni、Kamil Masood、Joseph K. Swabeck、George A. Olah
DOI:10.1002/anie.201205850
日期:2012.11.26
Owing to their unique properties, molecules containing the difluoromethyl group (CF2H) are of great interest. Tributyl(difluoromethyl)stannane has now been used for the selective and efficient direct ipso difluoromethylation of aryl iodides, heterocyclic iodides, and β‐styryl halides (see scheme). The straightforward preparation of the difluoromethylating reagent makes this approach particularly valuable
The study of transition-metal difluorocarbene complex has long been a subject of active investigation, but the transition-metal-catalyzed transfer of difluorocarbene remains a significant challenge. The Pd-catalyzed transfer of difluorocarbene is described to realize the coupling reaction of boronic acids with difluorocarbene to give (difluoromethyl)arenes and -olefins. Mechanistic investigations reveal
The preparation of the thermally stable, well-defined NHC-ligated difluoromethylated silver complexes la,b is described. The complexes were fully characterized, and the structural assignments were ambiguously further confirmed by single-crystal X-ray diffraction. Reactions of [(SIPr)Ag(CF2H)] with a variety of activated electrophiles such as diaryliodonium salts, vinyl(aryl)iodonium salts, aryldiazonium salts, and acid chlorides in the presence or absence of CuI occurred smoothly at room temperature to generate difluoromethylated compounds in good to excellent yields.