New Iridacyclohexadienes and Iridabenzenes by [2+2+1] Cyclotrimerization of Alkynes and Facile Intel-conversion between Iridacyclohexadienes and Iridabenzenes

摘要

Iridabenzenes [Ir{=CHCH=CHCH=C(CH_2R)}(CH_3CN)_2(PPh_3)_2]~(2+) (R=Ph 4a,P=p-C_4H_6CH_3 4b) are obtained from the reactions of H~+ with iridacyclohexadienes [Ir{=CH=CHCH=CHC(=CH-pC_6H_4R')}(CO)(PPh_3)_2]~+ (R'=H,3a,R'=CH_3,3b),which are prepared from [2+2+1] cyclotrimerization of alkynes in the reactions of [Ir(CH_3CN)(CO)(PPh_3)_2]~+ with HC=CH and HC ident to CR.