0価ニッケル錯体触媒を用いたC-HおよびC-C結合活性化を含む3成分カップリング反応の開発

抄録

The studies on nickel(0)-catalyzed three-component reactions via C-H and C-C bond activation were described. Highly regio- and stereoselective cross-trimerization of alkynes proceeded to give the corresponding 1,3-diene-5-yne by combination of triisopropylsilylacetylene and identical or distinct two alkynes via selective terminal C-H bond activation of triisopropylsilylacetylene in the presence of Ni(cod)₂/phosphine catalyst. The methodology could be also extended toward the three-component reaction among two alkynes and a norbornene to give the 1,5-enyne. On the other hand, our interest also focused on three-component reductive coupling reaction between ring-strained cyclic alkene, aryl aldehyde and silane. Using methylenecyclopropane, reductive coupling reaction with aryl aldehyde and triisopropylsilane proceeded to yield silylated allylic alcohols via C-C bond cleavage of methylenecyclopropane ring in the presence of Ni(cod)₂/NHC catalyst. We also found an unprecedented three-component reductive coupling via aromatic C-H bond activation of aryl aldehyde at the ortho position by combination with norbornene and triisopropylsilane leading to silylated indanol using Ni(cod)₂/NHC catalyst.