Some recent results in nucleophilic trifluoromethylation and introduction of fluorinated moieties

Abstract

Apart from the use of (trifluoromethyl)trimethylsilane, the scope of which has been broadened to the synthesis of trifluoromethyl sulfides, especially those that are bio-active, new and mild processes for the nucleophilic trifluoromethylation of non-enolizable carbonyl compounds or disulfides have been discovered from fluoroform or hemiaminals of trifluoroacetaldehyde and their derivatives. Very stable hemiaminals of fluoral (as well as their silyl ethers), readily prepared from commercially available hemiketals, have been designed as new trifluoromethylating agents. Besides their trifluoromethylating ability, they can be transformed into silyl or methyl ethers, which behave, as efficient generators of α-(trifluoromethyl)iminiums salts and equivalents of difluoromethylcarboxyl anions, respectively.