Rational Synthesis of Contra-Thermodynamic Spiroacetals by Reductive Cyclizations
作者:Leo R. Takaoka、Alexandre J. Buckmelter、Thomas E. LaCruz、Scott D. Rychnovsky
DOI:10.1021/ja044642o
日期:2005.1.1
A synthesis of spiroacetals was developed using a reductive cyclization strategy that leads stereoselectively to spiroacetals with a single anomeric stabilization. The method begins with the synthesis of spiro ortho esters. The ortho ester is converted to a cyano acetal. Reductive lithiation of the cyano acetal generates an axial dialkoxylithium reagent, and intramolecular cyclization produces a new