Palladium-Catalyzed Three-Component Reaction of Allenes, Aryl Iodides, and Diazo Compounds: Approach to 1,3-Dienes

摘要

1,3-Dienes are very useful intermediates in organic synthesis because of their rich structural and reaction properties. Consequently, enormous efforts have been devoted to the regio- and stereoselective synthesis of 1,3-dienes. Among the various methods developed in the past decades for the synthesis of 1,3-dienes, the metal-catalyzed intermolecular enyne coupling is a straightforward and atom-efficient approach. In 1991, Mitsudo and co-workers reported a ruthenium-catalyzed intermolecular co-dimerization of electron-rich alkynes with a,(3-unsaturated alkenes to give 1,3-dienes.Later on, rhodium-, palladium-, and cobalt-catalyzed 1,3-diene syntheses from alkynes and alkenes were reported (Scheme 1 a; M = Ru, Rh, Pd, Co).However, the examples of intermolecular coupling of alkynes with olefins are still limited, in contrast to the corresponding intramolecular enyne isomerization.