stereogenic double bonds is described. A combination of the highly Lewis acidic [Cu(S,S)-tert-Bu-box}](H2O)2(SbF6)2 complex and molecular sieves served as catalyst and afforded the Claisen rearrangement products, substituted and functionalized α-keto esters, in high yield with a remarkable diastereo- and enantioselectivity. The influence of ligand structure, counterion and allyl vinyl ether double bond configuration
The total synthesis of an alkylcitrate secondary metabolite from the fungi Trichodema viride is described. An ester dienolate [2,3]-Wittig rearrangement and a S. Julia-Kocienski olefination served as key C/C-connecting transformations. The highly convergent synthesis consists of a longest linear sequence of 17 steps. (C) 2004 Published by Elsevier Ltd.