Regioselectivity of MAO-catalyzed allylmetallation of conjugated enynes with allylzirconiums
摘要:
Various conjugated enynes 1 were subjected to the MAO-catalyzed reaction with the allylzirconium, generated by hydrozirconation of allenes. In light of the regiochemisty, the C-C bond formation occurs exclusively between the alpha carbon of the allylzirconium and the "yne" part of the conjugated enyne 1. Steric demand of the alpha-substituent X in 1 is the decisive factor for determing the the reactive site for 1. (C) 1998 Elsevier Science Ltd. All rights reserved.