Trifluoromethyl Ketones from Enolizable Carboxylic Acids via Enediolate Trifluoroacetylation/Decarboxylation
摘要:
Primary and secondary (enolizable) carboxylic acids were converted in a single step to trifluoromethyl ketones. Treatment of the acid with 2.2 equiv of LDA generated an enediolate that was trifluoroacetylated with EtO2CCF3. Quenching the reaction mixture with aqueous HCI resulted in rapid decarboxylation and provided the trifluoromethyl ketone product in good yield. The process may be performed at -20 degrees C with a slight reduction in yield. The reaction was extended to the preparation of pentafluoroethyl and chlorodifluoromethyl ketones.
Stereoconvergent Negishi Arylations of Racemic Secondary Alkyl Electrophiles: Differentiating between a CF<sub>3</sub> and an Alkyl Group
作者:Yufan Liang、Gregory C. Fu
DOI:10.1021/jacs.5b04725
日期:2015.8.5
wide array of enantioconvergent cross-couplings of arylzincreagents with CF3-substituted racemic secondary alkyl halides, a process that necessitates that the chiral catalyst be able to effectively distinguish between a CF3 and an alkyl group in order to provide good ee. We further demonstrate that this method can be applied without modification to the catalyticasymmetric synthesis of other families
Facile syntheses of gem-difluoroalkenes from chlorodifluoromethylketones
作者:Jean-Pierre Bégué、Danièle Bonnet-Delpon、Jonathan M. Percy、Michael H. Rock、Robin D. Wilkes
DOI:10.1039/c39950001857
日期:——
Chlorodifluoromethyl ketones reacted with diazomethane to afford epoxides in high yield; upon treatment with butyllithium, the epoxides underwent efficient ring opening to afford 3,3-difluoro-2-alkyl-alken-1-ols, suitable substrates for sigmatropic rearrangement leading to compounds containing a CF2 group in mid-chain.
This invention relates to compounds and pharmaceutical compositions, and methods for inhibiting or preventing the amyloid protein deposits in the brain which are associated with Alzheimer's disease and aged Down's syndrome patients. More particularly, it relates to the treatment of Alzheimer's disease.
Synthetic routes to lactones with a chlorodifluoromethyl group via S(N)2', oxidation and lactonization reactions, were described. (C) 2004 Elsevier B.V. All rights reserved.
A microbially-based approach for the synthesis of chiral secondary alcohols bearing the difluoromethyl or chlorodifluoromethyl group
A synthetic approach to both enantiomers of the secondary alcohols [Ph(CH2)n CH(OH)CXF2 (n = 0-2) C6H13(CH2)n CH(OH)CFX2 (n = 0 or 2) and CXF2CH(OH)CH2CO2Et [X = H or Cl], involving the stereoselective hydrolysis of ester derivatives, is described. The absolute configurations of these difluoromethylated or chlorodifluoromethylated molecules were determined.