Not a Diels-Alderreaction but a 1,4-hydrovinylation takes place on treatment of 1,3-dienes with functionalized alkenes in the presence of the catalyst system [CoBr2 (dppe)]/ZnI2 /Bu4 NBH4 (dppe = 1,2-bis(diphenylphosphanyl)ethane). With this reaction the 1,4-dienes with different substituents R1 -R4 can be obtained in high selectivity and good to excellent yields.
Cobalt(I)-catalyzed 1,4-Hydrovinylation Reactions of 1,3-Dienes with Functionalized Terminal Alkenes under Mild Conditions
作者:Gerhard Hilt、Steffen Lüers
DOI:10.1055/s-2002-23549
日期:——
of acyclic 1,3-dienes with various functionalized terminal alkenes is described. The mild reaction conditions are significant because they considerably reduce the amount of side products and for non acceptor-substituted alkenes the branched products are formed exclusively. The CoBr 2 (dppe) catalyst system controls the regiochemistry of the hydrovinylation process. Unsymmetrical 1,3-dienes yield products