Eu(fod)(3)-catalyzed rearrangement of allylic esters possessing a chelating site. Application to enediyne synthesis

A number of 1,2-dialkynyl-3-alkyl or 3-aryl allylic esters underwent a facile Eu(fod)(3)-catalyzed rearrangement at 20-132 degrees C to give exclusively cis-enediynes. The esters capable of forming a chelate with Eu(In) exhibited a remarkably enhanced reactivity; the C-3 aryl group facilitated the rearrangement as well. (C) 1999 Elsevier Science Ltd. All rights reserved