Synthesis of Novel Rhenium(I) Enolate Complexes as Active Key Intermediates in the Catalytic Aldol Type Reaction

Rhenium(I) dinitrogen complex cis-ReH(N2)(PMe2Ph)4 catalyzes an aldol type reaction of ethyl cyanoacetate with benzaldehyde under moderate conditions. Rhenium enolate complexes Re(NCCRCO2R′)(NCCHRCO2R′)(PMe2Ph)4 (R = H, R′ = Me; R = H, R′ = Et; R = H, R′ = n-Bu; R = Me, R′ = Et) and Re(NCCHCO2Et)[NC(EtO2C)C=CHPh](PMe2Ph)4 as active intermediates of the aldol type reactions have been isolated.