Stereocontrolled Synthesis of β-Difluoromethylated Materials
摘要:
Investigation of synthetic routes for regio- and stereocontrolled fluorinated materials with a difluoromethyl group, using ethyl bromodifluoroacetate as a starting material, is described. In particular, (E)-difluoromethylated trisubstituted olefins were prepared via the proton migration reaction catalyzed by using fluoride anion. Further, optically active beta-difluoromethyl esters were obtained by the enzymatic resolution.
Catalytic Asymmetric Hydrogenation of α-CF<sub>3</sub>- or β-CF<sub>3</sub>-Substituted Acrylic Acids using Rhodium(I) Complexes with a Combination of Chiral and Achiral Ligands
作者:Kaiwu Dong、Yang Li、Zheng Wang、Kuiling Ding
DOI:10.1002/anie.201307903
日期:2013.12.23
Only the mixture works! Acrylic acid derivatives with CF3 substituents in α or β position were efficiently hydrogenated in the presence of a RhI complex with a chiral secondary phosphine oxide (SPO; see scheme) and an achiral Ph3P as ligands. The corresponding propanoic acid derivatives were obtained with generally high conversion (>99 %) and high enantioselectivity (92–>99 %).