Simple preparation of enantiomeric Michael adducts of thiophenol to chalcones: easily available new chiral building blocks
作者:Jacek Skarżewski、Mariola Zielińska-Błajet、Ilona Turowska-Tyrk
DOI:10.1016/s0957-4166(01)00330-5
日期:2001.7
A facile and enantioselective method for the multigram preparation of the title compounds is described. The Michael addition of thiophenols to chalcones catalyzed by (+)-cinchonine, followed by crystallization, led to the corresponding adducts 2 in up to > 95% e.e. The stereoselective Beckmann rearrangement of the oxime of (+)-1,3-diphenyl-3-phenylsulfanylpropan-1-one 2a gives the anilide of (R)-(+)-3-phenyl-3-phenylsulfanylpropanoic acid (as determined by X-ray analysis) and alcoholysis leads to the corresponding enantiomerically pure ethyl ester. (C) 2001 Elsevier Science Ltd. All rights reserved.