Trifluoromethylation of Nonenolizable Carbonyl Compounds with a Stable Piperazino Hemiaminal of Trifluoroacetaldehyde

Strategies for nucleophilic, electrophilic, and radical trifluoromethylations

“…Afterwards, Langlois and coworkers developed stable hemiaminals of fluoral 23 and their silylated derivatives 24 as powerful trifluoromethylating agents towards non-enolisable carbonyl compounds, disulfides, and diselenides under activation by a stoichiometric strong base or catalytic fluoride anion such as CsF, and TBAT (Scheme 23). Fluoroform or more conveniently fluoral methyl hemiketal served as starting material for preparation of 23 and 24 [63][64][65][66].…”

Nucleophilic trifluoromethylation of carbonyl compounds and derivatives

“…as well as derivatives of trifluoroacetic acid, 20 fluoral, 21 and trifluoroacetophenone, 22 and other have been employed as efficient reagents for nucleophilic trifluoromethylation.…”

Trifluoromethylation of Carbonyl Compounds

“…During the investigations to design new nucleophilic trifluoromethylating reagents, Langlois and co-workers described a family of suitable reagents, namely the hemiaminals of fluoral [82,83]. Trifluoroacetaldehyde (fluoral), in its hemiketal form (16), reacted with N-benzyl piperazine (17) giving piperazino hemiaminal (18) [83].…”

“…Trifluoroacetaldehyde (fluoral), in its hemiketal form (16), reacted with N-benzyl piperazine (17) giving piperazino hemiaminal (18) [83]. This is a stable compound which, after silylation, gave the corresponding Osilylated hemiaminal (19) which is able to trifluoromethylate nonenolizable carbonyl compounds (20) into trifluoromethyl carbinols (21) [83] (Scheme 26).…”