The first general method for α-trifluoromethylation of carboxylic acids using BrF₃

Abstract

2-Carbomethoxy-1,1-bis(methylsulfide)-1-alkenes, easily made from carboxylic acids, CS(2) and MeI, were treated with BrF(3) producing eventually the desired alpha-trifluoromethyl carboxylate derivatives--RCH(CF(3))COOR'--in good yields.

Chemical Modification of Oligonucleotides for Therapeutic, Bioanalytical and other Applications

“…The yield of 60 could, however, be substantially increased by using only a small excess of the reagent and terminating the reaction at the stage when only one methyl sulfide group was replaced. The bromodifluoro‐mono sulfide ( 61 ) thus obtained was subjected to oxidation (most efficiently with HOF⋅CH 3 CN43) and the resulting sulfone 62 treated with Bu 4 NF,44 forming the α‐trifluoromethyl carboxylate 60 in respectable 60 to 70% yields (Scheme ) 45…”

Umpolung of Fluoroform by CF Bond Activation: Direct Difluoromethylation of Lithium Enolates

“…[1, 3,4] In particular, the treatment of fluoroform with sodium or potassium alkoxide in DMF affords its trifluoromethyl adduct. [5] Fluoroform can thus be employed as the nucleophilic trifluoromethyl carbanion equivalent for non-enolizable carbonyl compounds.…”

Selective Reactions of Bromine Trifluoride in Organic Chemistry

“…The bromodifluoro-mono sulfide (61) thus obtained was subjected to oxidation (most efficiently with HOF·CH 3 CN [43] ) and the resulting sulfone 62 treated with Bu 4 NF, [44] forming the a-trifluoromethyl carboxylate 60 in respectable 60 to 70% yields (Scheme 16). [45] With secondary carboxylic acids the reaction proceeded differently since no olefinic centers as in 58 could be formed. Instead, the reaction of carboxylates with CS 2 under basic conditions resulted in a-dithio esters (63).…”