Catalytic aerobic oxidative decarboxylation of α-trifluoromethyl-α-hydroxy acids to trifluoromethyl ketones
摘要:
The oxidative decarboxylation of alpha-trifluoromethyl-alpha-hydroxy acids to trifluoromethyl ketones is carried out under mild catalytic aerobic conditions using a cobalt(Ill) complex in the presence of pivalaldehyde. (C) 2002 Elsevier Science Ltd. All rights reserved.
(1-Naphthyl)(trifluoromethyl) <i>O</i>-Carboxy Anhydride as a Chiral Derivatizing Agent: Eclipsed Conformation Enforced by Hydrogen Bonding
作者:Olivier Thillaye du Boullay、Aurélie Alba、Fatima Oukhatar、Blanca Martin-Vaca、Didier Bourissou
DOI:10.1021/ol801930m
日期:2008.10.16
The preparation of the (1-naphthyl)(trifluoromethyl) O-carboxy-anhydride 1 and its use as a chiral derivatizing agent with several a-chiral primary amines are reported. The very large Delta delta(RS) values observed in H-1 NMR have been correlated with a marked preference of the corresponding alpha-hydroxy-am ides for the eclipsed conformation. In comparison, the related O-methylated amides are shown to adopt staggered conformations, which substantiates the critical role of intramolecular hydrogen bonding in maximizing the anisotropic effect.
Long-Range Shielding Effects in the <sup>1</sup>H NMR Spectra of Mosher-like Ester Derivatives
作者:Thomas R. Hoye、Sara E. Erickson、Sherrie L. Erickson-Birkedahl、Christopher R. H. Hale、Enver Cagri Izgu、Michael J. Mayer、Patrick K. Notz、Matthew K. Renner
DOI:10.1021/ol1003862
日期:2010.4.16
differences (Δδs) in the two diastereomers of menthyl esters of known chiral derivatizing agents (CDAs) were compared to those of the α-methoxy-α-trifluoromethyl-1-naphthylacetyl (MTN(1)A) analogues I. Discrimination of the terminal diastereotopic methyl resonances in esters of the homologous, symmetrical carbinols II was evaluated. Remarkably, the methyls differed in the MTN(1)A esters III even when
Catalytic aerobic oxidative decarboxylation of α-trifluoromethyl-α-hydroxy acids to trifluoromethyl ketones
作者:Gonzalo Blay、Isabel Fernández、Alicia Marco-Aleixandre、Belén Monje、José R Pedro、Rafael Ruiz
DOI:10.1016/s0040-4020(02)00947-x
日期:2002.10
The oxidative decarboxylation of alpha-trifluoromethyl-alpha-hydroxy acids to trifluoromethyl ketones is carried out under mild catalytic aerobic conditions using a cobalt(Ill) complex in the presence of pivalaldehyde. (C) 2002 Elsevier Science Ltd. All rights reserved.