Pd-Catalyzed α-Arylation of α,α-Difluoroketones with Aryl Bromides and Chlorides. A Route to Difluoromethylarenes
作者:Shaozhong Ge、Wojciech Chaładaj、John F. Hartwig
DOI:10.1021/ja501117v
日期:2014.3.19
α-difluoroketones with aryl and heteroaryl bromides and chlorides catalyzed by an air- and moisture-stable palladacyclic complex containing P(t-Bu)Cy2 as ligand. The combination of this Pd-catalyzed arylation and base-induced cleavage of the acyl–aryl C–C bond within the α-aryl-α,α-difluoroketone constitutes a one-pot, two-step procedure to synthesize difluoromethylarenes from aryl halides. A broad range
Sandmeyer Difluoromethylation of (Hetero-)Arenediazonium Salts
作者:Christian Matheis、Kévin Jouvin、Lukas J. Goossen
DOI:10.1021/ol5030037
日期:2014.11.21
straightforward conversion of (hetero-)arenediazonium salts into the corresponding difluoromethyl (hetero-)arenes under mild conditions. The actual difluoromethylating reagent, a difluoromethyl–copper complex, is formed in situfrom copper thiocyanate and TMS–CF2H. The diazonium salts are either preformed or generated in situfrom broadly available aromatic amines.
The palladium-catalyzed Negishi cross-couplingreaction of aryl iodides and bromides with (difluoromethyl)zinc reagent bearing a diamine such as TMEDA is achieved to provide the difluoromethylated aromatic compounds in good to excellent yields. The advantages of (difluoromethyl)zinc reagent are that (1) the derivatives, which possess different stability and reactivity, can be readily prepared via ligand
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.
SONDEJ S. C.; KATZENELLENBOGEN J. A., J. ORG. CHEM., 51,(1986) N 18, 3508-8513