PaaSicats: Powerful catalysts for asymmetric epoxidation of enones. Novel syntheses of α-arylpropanoic acids including (S)-fenoprofen
作者:Lydia Carde、Huw Davies、Thomas P. Geller、Stanley M. Roberts
DOI:10.1016/s0040-4039(99)01022-9
日期:1999.7
Application of the recently developed silica-adsorbed polyleucine catalysts to the enantioselective epoxidation of Two enones is reported. Treatment of these epoxides with trimethylaluminium in moist dichloromethane generates the alpha-hydroxy-beta-methylketones, with inversion of configuration. Diastereoselective reduction of the ketone moiety followed by oxidative cleavage generates alpha-arylpropanoic acids. (C) 1999 Elsevier Science Ltd. All rights reserved.
Stereocontrolled ring-opening of some enantiomerically enriched epoxy ketones and epoxy alcohols using trimethylaluminium: synthesis of (S )-2-arylpropanoic acids
作者:Lydia Carde、D. Huw Davies、Stanley M. Roberts
DOI:10.1039/b000996m
日期:——
cleavage furnished (S)-2-phenylpropanoic acid 11. In a complementary sequence epoxy ketones (−)-6 and 25 were converted into (S)-2-phenylpropanoic acid and (S)-fenoprofen 5 respectively by reduction with zinc borohydride, reaction with trimethylaluminium and oxidative cleavage. Similarly epoxy ketones (−)-6, 21 and 28 were treated with methylmagnesiumiodide, trimethylaluminium and the resultant alcohols subjected