Synthesis of optically active gem-difluorinated organic molecules attracts a great deal of interest due to their unique properties in pharmaceutical and agrochemical areas. Herein, a series of enantioenriched α,α-difluoro-β-arylbutanoic esters were prepared in high yields (83–99%) with moderate to excellent enantioselectivities (≤97:3 er) by palladium-catalyzed asymmetrichydrogenation.
Ligand-Controlled Regiodivergent Palladium-Catalyzed Decarboxylative Allylation Reaction to Access α,α-Difluoroketones
作者:Ming-Hsiu Yang、Douglas L. Orsi、Ryan A. Altman
DOI:10.1002/anie.201410039
日期:2015.2.16
α,α‐Difluoroketones possess unique physicochemical properties that are useful for developing therapeutics and probes for chemical biology. To access the α‐allyl‐α,α‐difluoroketone substructure, complementary palladium‐catalyzed decarboxylative allylation reactions were developed to provide linear and branched α‐allyl‐α,α‐difluoroketones. For these orthogonal processes, the fluorination pattern of the
Kinetic resolution of 2,2-difluoro-3-hydroxy-3-aryl-propionates catalyzed by organocatalyst (R)-benzotetramisole
作者:Hui Zhou、Qing Xu、Peiran Chen
DOI:10.1016/j.tet.2008.04.055
日期:2008.6
Kinetic resolution of a series of ethyl 2,2-difluoro-3-hydroxy-3-aryl-propionates catalyzed by (R)-benzotetramisole has been performed. It was found that when the aryl group was phenyl or phenyl substituted with electron-donating group (such as -Me, -OMe, and -SMe) or naphthyl groups, the enantio-selectivity factor (s) could reach 20 or higher; electron-withdrawing (such as fluorine) substitution on the benzene ring dramatically lowers the s value. Kinetic resolution in preparative scale for some of the substrates demonstrated the applicability of this method. (c) 2008 Elsevier Ltd. All rights reserved.
The Mitsunobu reaction in the synthesis of α,α-difluoro-β-amino acids
作者:Natalie A. Fokina、Andrei M. Kornilov、Valery P. Kukhar
DOI:10.1016/s0022-1139(01)00430-4
日期:2001.9
A three-stage strategy is proposed to prepare alpha,alpha -difluoro-beta -amino acids starting from aldehydes and with ethyl bromodifluoroacetate as a fluorine source. The Mitsunobu reaction as a key step was studied by P-31 and F-19 NMR for alkyl- and aryl-substituted alpha,alpha -difluoro-beta -hydroxyesters and performed under optimized conditions giving the target compounds. (C) 2001 Elsevier Science B.V. All rights reserved.