Methods for nucleophilic fluoromethylation

摘要

A novel, convenient and efficient method for trifluoromethylation of substrate compounds is disclosed. Particularly, alkoxide and hydroxide induced nucleophilic trifluoromethylation of carbonyl compounds, disulfides and other electrophiles, using phenyl trifluoromethyl sulfone PhSO₂CF₃ (or sulfoxide PhSOCF₃) is disclosed. A method of both symmetrical and unsymmetrical anti-2,2-difluoropropan-1,3-diols with high diastereoselectivity (up to 94% de) is disclosed using difluoromethyl phenyl sulfone. This unusual type of high diastereoselectivity was obtained via an intramolecular charge-charge repulsion effect rather than the traditional steric control (based on the Cram's rule). Thus, difluoromethyl phenyl sulfone can be used as a novel difluoromethylene dianion species ("^-CF2^-"), which can couple two electrophiles (such as diphenyl disulfide or non-enolizable aldehydes) to give new difluoromethylenated products.