under conditions (pressure (40 bar), temperature (25°C) and reaction times (2 h)) used for usual hydrogenation of ethyl pyruvate showed that the vinyl group is totally transformed into an ethyl (deuterated) and that H for D exchanges occur on the quinoline ring and at C9. Deuteration of ethyl pyruvate under the same conditions showed that no deuteration occurs at the chain-methyl, neither in toluene nor
Catalytic Enantioselective Fluorination of β-Keto Esters by Phase-Transfer Catalysis Using Chiral Quaternary Ammonium Salts
作者:Dae Young Kim、Eun Joo Park
DOI:10.1021/ol010281v
日期:2002.2.1
[reaction: see text] The catalyticenantioselective electrophilic fluorination promoted by quaternary ammonium salt from cinchonine as a phase-transfer catalyst is described. Treatment of beta-keto esters with N-fluorobenzenesulfonimide as the fluorine source under mild reaction conditions afforded the corresponding alpha-fluoro beta-keto esters in exellent yields with good to moderate enantiomeric