Nucleophilic difluoromethylation of epoxides with PhSO(NTBS)CF₂H by a preorganization strategy.

Unlike the facile synthesis of β-monofluoromethyl alcohols by nucleophilic monofluoromethylation of epoxides, the synthesis of β-difluoromethyl alcohols by nucleophilic difluoromethylation of epoxides still remains a challenge. Herein, studies on tackling this problem with PhSO(NTBS)CF2H (2; TBS=tert-butyldimethylsilyl) are reported. The preorganization of 2 and epoxides with BF3⋅Et2O was found to be crucial for the reaction. The reaction shows excellent regioselectivity and has a broad substrate scope. The facile transformation of the ring-opened products to β-difluoromethyl, γ-difluoromethyl, and β-difluoromethylenyl alcohols demonstrates the synthetic utility of the reaction.