We developed an efficient, practical, robust method for the regio-and stereoselective preparation of (E)-ketene trimethylsilyl acetals (KSAs) derived from tert-butyl esters 1. The reaction was performed under convenient reaction conditions; LDA-TMSCl, 0-5° C, and cyclopentyl methyl ether (CPME) solvent. Two kinds of (Z)-and (E)-KSAs derived from α- oxygen and α-nitrogen-substituted tert-butyl esters, respectively, were also obtained in ...
[Heathcock, Clayton H.; Buse, Charles T.; Kleschick, William A.; Pirrung, Michael C.; Sohn, John E.; Lampe, John Journal of Organic Chemistry, 1980 , vol. 45, # 6 p. 1066 - 1081]