Chiral orthoesters in organic synthesis: Novel reagents for the enantioselective acylation of silylenolethers
作者:Luigi Longobardo、Giovanna Mobbili、Emilio Tagliavini、Claudio Trombini、Achille Umani-Ronchi
DOI:10.1016/s0040-4020(01)90792-6
日期:1992.1
Dialkyl trans-2-alkoxy-2-alkyl-1,3-dioxolan-4,5-dicarboxylates and the corresponding N,N,N,N-tetramethyl-4,5-diamides have been prepared respectively from dialkyl tartrates or tartaric acid diamides. They smoothly reacted with silylenolethers in the presence of Lewis acids to give enantiomerically enriched (up to 90% d.e.) monoprotected 1,3-diketones. A dramatic dependence of the stereochemical outcome from the configuration of the enolic double bond of 4 has been observed. The products can be stereoselectively reduced to give configurationally defined monoprotected 3-ketols.