Carbene-Induced Intra- vs Intermolecular Transfer-Fluoromethylation of Aryl Fluoromethylthio Compounds under Rhodium Catalysis
摘要:
The intra- vs intermolecular transfer-fluoromethylation of aryl fluoromethylthio compounds is proposed. Finely designed ArSCF3 (la) nicely releases its trifluoromethyl (CF3) group intermolecularly under rhodium catalysis, whereas a difluoromethylated analogue, ArSCF2H compound lb shows intramolecular reaction.
A highly efficient Rh-catalyzed carbenoid addition to trifluoromethylthioether for the formation of trifluoromethyl-substituted sulfonium ylide is described. The trifluoromethyl-substituted sulfonium ylide can act as an electrophilic trifluoromethylation reagent, as demonstrated by trifluoromethylation of β-ketoesters and aryl iodides.
reagents (trifluoromethyl)(4-nitrophenyl)bis(carbomethoxy)methylide (1g) and (trifluoromethyl)(3-chlorophenyl)bis(carbomethoxy)methylide (1j) through structure-activity study was described. Under mild conditions, reagent 1g reacted with β-ketoesters and silyl enol ethers to give α-trifluoromethylated-β-ketoesters or α-trifluoromethylated ketones in high yields. In addition, reagent 1g could serve as