Cross-metathesis of α-methylene-β-lactams: the first tetrasubstituted alkenes by CM
作者:Yanke Liang、Ravinder Raju、Tri Le、Christopher D. Taylor、Amy R. Howell
DOI:10.1016/j.tetlet.2008.12.060
日期:2009.3
α-Alkylidene-β-lactams have been prepared in good to excellent yields by olefin cross-metathesis. Electron-poor α-methylene-β-lactams undergo cross-metathesis more rapidly and efficiently than more electron-rich analogs. Significantly, tetrasubstituted alkenes have for the first time been accessed by CM reactions.
Optically pure 4-acetoxy-3-[1-(t-butyldimethylsilyloxy)ethyl]-2- azetidinone(), which is a highly versatile intermediate for the synthesis of thienamycin() and other biologically active [β-lactam analogs, was synthesized from 4-carboxy-3-[1-(t-butyldimethylsilyloxy)ethyl]-2-azetidinone() by Kolbe-type electrolysis.