摘要:
Simply generated (TiCl4, Et3N, -78-degrees-C) titanium enolates of some thioesters and alpha-thio substituted esters undergo aldol condensations with achiral and chiral aldehydes with low to high stereoselectivity. An H-1-NMR study of the TiCl4/ester complexation and of the enolization process is presented. The relation between the enolate structure and the aldol product stereochemistry is discussed.