Synthesis of trifluoromethyl carbinols
In the presence of molecular sieves in DMSO, trifluoromethylation of various aldehydes and ketones with trifluoromethyltrimethylsilane proceeded very smoothly to give the corresponding trifluoromethylated adduct in good to quantitative yields without a base catalyst.
K. Iwanami, T. Oriyama, Synlett, 2006, 112-114.
The use of TMS-CF3 enables a versatile nucleophilic trifluoromethylation of carbonyl compounds. The reaction is induced by fluoride ions.
G. K. S. Prakash, R. Krishnamurti, G. A. Olah, J. Am. Chem. Soc., 1989, 111, 393-395.
A stable (trifluoromethyl)zinc reagent can be generated from CF3I and ZnEt2. Trifluoromethylation of carbonyl compounds proceeds smoothly with diamine as a ligand and ammonium salt as an initiator. Moreover, the (trifluoromethyl)zinc reagent can also be employed as a difluorocarbene source for gem-difluoroolefination of carbonyl compounds as well as gem-difluorocyclization of alkenes or alkynes.
K. Aikawa, W. Toya, Y. Nakamura, K. Mikami, Org. Lett., 2015, 17, 4966-4999.
An amidinate salt of hexafluoroacetone hydrate is a powerful and air-stable reagent for the preparation of fluorinated organic molecules. This reagent is soluble in many polar organic solvents and produces fluoroform, following the release of trifluoroacetate. Reactions with this reagent and common electrophiles provide excellent yields of trifluoromethylated products.
M. V. Riofski, A. D. Hart, D. A. Colby, Org. Lett., 2013, 15, 208-211.
A nucleophilic trifluoromethylation reaction of carbonyl compounds with Ruppert’s reagent, Me3SiCF3, was efficiently promoted by a P(t-Bu)3-DMF system. Imines were also converted to the desired α-trifluoromethyl amines under similar reaction conditions.
S. Mizuta, N. Shibata, T. Sato, H. Fujimoto, S. Nakamura, T. Toru, Synlett, 2006, 267-270.
Mercury(II) chloride efficiently activates magnesium metal to induce a desulfonylative trifluoromethylation process. The new reductive trifluoromethylation provides an alternative method for efficient trifluoromethylation of non-enolizable or enolizable aldehydes with readily available phenyl trifluoromethyl sulfone reagent.
Y. Zhao, J. Zhu, C. Ni, J. Hu, Synthesis, 2010, 1899-1904.
N-Heterocyclic Carbene Catalyzed Highly Chemoselective Intermolecular Crossed Acyloin Condensation of Aromatic Aldehydes with Trifluoroacetaldehyde Ethyl Hemiacetal
B. T. Ramanjaneyulu, S. Mahesh, R. V. Anand, Org. Lett., 2015, 17, 6-9.