Di-, tri-, and tetrasubstituted β-lactones are accessible in a one-step procedure by a Reformatskyreaction of phenyl α-bromoalkanoates with ketones or aldehydes at a sacrificial indium anode. With indium powder comparable results are obtained. The yield of β-lactones is significantly lower, if zinc is used instead of indium.
Asymmetric synthesis of tetrahydrolipstatin and valilactone
作者:Stephen C. Case-Green、Stephen G. Davies、Paul M. Roberts、Angela J. Russell、James E. Thomson
DOI:10.1016/j.tetasy.2008.11.012
日期:2008.11
The highly diastereoselective aldol reaction between acyl complexes of the iron chiral auxiliary [(eta(5)-C5H5)Fe(CO)(PPh3)] and beta-hydroxy aldehydes (obtained via a Noyori asymmetric hydrogenation), followed by a tandem oxidative decomplexation-cyclisation process gives access to beta-substituted and alpha,beta-disubstituted beta-lactones in high ee. This methodology has been employed in the asymmetric syntheses of tetra hydrolipstatin and valilactone. (C) 2008 Elsevier Ltd. All rights reserved.