The Ruppert–Prakash reagent is the most powerful and well-documented reagent for trifluoromethylation. Despite its versatility, no general method exists for its use in a flow system. Here we report the first flow trifluoromethylation of carbonylcompounds and its utility for drug synthesis of efavirenz and HSD-016, including preliminary results of enantioselective variants.
A truly catalytic nucleophilic trifluoromethylation reaction of carbonyl compounds with Ruppert’s reagent, Me3SiCF3, has been shown to be efficiently promoted by a P(t-Bu)3-DMF system. Imines were also converted to the desired α-trifluoromethyl amines under similar reaction conditions.
The first Lewis acid-catalyzed trifluoromethylation reactions of aldehydes with Me3SiCF3 under TiF4/DMF, Ti(OiPr)4/DMF and Cu(OAc)2/dppp/toluene conditions are described. We have successfully applied this methodology to the difluoromethylation of aldehydes using Me3SiCF2SePh, Me3SiCF2P(O)OEt2 and Me3SiCF2SPh.
Ammonium bromides/KF catalyzed trifluoromethylation of carbonyl compounds with (trifluoromethyl)trimethylsilane and its application in the enantioselective trifluoromethylation reaction
has been performed by treatment of Me3SiCF3 under initiation by TBAF, TBAT, TMAF as well as CsF. However, these commercially available fluorides are rather expensive and moisture sensitive. Potassiumfluoride (KF) is an inexpensive and commonly used fluoridesource and can be also used as an initiator for the trifluoromethylation, but the method suffers from the significant limitation that only DMF
TBD-Catalyzed Trifluoromethylation of Carbonyl Compounds with (Trifluoromethyl)trimethylsilane
作者:S. Matsukawa、S. Takahashi、H. Takahashi
DOI:10.1080/00397911.2011.644381
日期:2013.6.3
Abstract Trifluoromethylation of carbonylcompounds using (trifluoromethyl) trimethylsilane catalyzed by 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) afforded the corresponding α-trifluoromethyl alcohols in good to excellent yields under mild reaction conditions. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental