NUK - logo
E-viri
Celotno besedilo
Recenzirano Odprti dostop
  • Copper‐Catalyzed Enantiosel...
    Wei, Zhiqiang; Zheng, Weiqin; Wan, Xiaolong; Hu, Jinbo

    Angewandte Chemie, September 11, 2023, Letnik: 135, Številka: 37
    Journal Article

    Molecules containing a difluoromethyl group or a propargylic stereocenter are widely used in pharmaceuticals and agrochemicals, and 1,2‐functionalization of olefins is an important method for introducing the two groups into molecules simultaneously. The construction of the propargylic stereocenter with terminal alkynes usually requires bases. However, difluoromethylating agents with high reduction potentials often decompose in the presence of bases because of their acidities, and those with low reduction potentials are stable but difficult to undergo the desired single electron transfer (SET) reduction. Using the linear relationship between reduction potential differences (ΔE) and Hammett substituent constants (σ) of difluoromethyl aryl sulfones, we solved the dilemma between acidities and reduction potentials of difluoromethylating agents. Herein, we report the first enantioselective difluoromethylation‐alkynylation of olefins with difluoromethyl 4‐chlorophenyl sulfone with high enantioselectivity (>90 % ee). We also extended this asymmetric fluoroalkylation‐alkynylation reaction with other fluoroalkyl sulfones, which enabled efficient installation of trifluoromethyl, difluoroalkyl, difluorobenzyl, (benzenesulfonyl)‐difluoromethyl and monofluoromethyl groups into products. The linear relationship between reduction potential differences (ΔE) and substituent constants (σ) of aryl difluoromethyl sulfones provides a powerful strategy to solve the dilemma of acidities and reduction potentials of difluoromethylating agents. The strategy enabled achieving enantioselective difluoromethylation‐alkynylation reactions of olefins with difluoromethyl 4‐chlorophenyl sulfone.