UNUSUAL AND EFFICIENT (Z)-STEREOSELECTIVE PETERSON SYNTHESIS OF 2-DIETHOXYPHOSPHONYL-1-ALKOXY-3-METHYLPENTA-1,3-DIENES - THEIR USE IN THE DIELS-ALDER REACTION

摘要

The lithiated anion of diethyl alpha-trimethylsilyl-prenylphosphonate, readily in situ generated from diethyl prenylphosphonate, reacts smoothly with various alkyl formates to give the title compounds with exclusive 1-(Z)-geometry and in high isolated yield. The [4 + 2] cycloaddition reaction of dienes 3 with electron-deficient dienophiles is described. (C) 1996 Published by Elsevier Science Ltd [References: 17]