Practical and robust method for regio- and stereoselective preparation of (E)-ketene tert-butyl TMS acetals and beta-ketoester-derived tert-butyl (1Z,3E)-1,3-bis(TMS)dienol ethers.
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 degrees C, and cyclopentyl methyl ether (CPME) solvent. Two kinds of (Z)- and (E)-KSAs derived from alpha-oxygen and alpha-nitrogen-substituted tert-butyl esters, respectively, were also obtained in good yield. The present protocol was successfully applied to a stereocontrolled preparation of useful, but highly reactive (less accessible) beta-ketoester-derived tert-butyl (1Z,3E)-1,3-bis(TMS)dienol ethers 2.
Okabayashi
Tomohito
T
Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan.
Iida
Akira
A
Takai
Kenta
K
Nawate
Yuuya
Y
Misaki
Tomonori
T
Tanabe
Yoo
Y