Rational synthesis of contra-thermodynamic spiroacetals by reductive cyclizations
LR Takaoka, AJ Buckmelter, TE LaCruz…
文献索引：Takaoka, Leo R.; Buckmelter, Alexandre J.; LaCruz, Thomas E.; Rychnovsky, Scott D. Journal of the American Chemical Society, 2005 , vol. 127, # 2 p. 528 - 529
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 ring with retention of configuration. The strategy ...
