1,1-Insertion of substituted alkynes into the Ir–O bond of η2-carboxylato iridium complexes

Alkyl-carbonyl-iridium [Ir(CH3)(CO)(η2-O2CR′)(PPh3)2]+ (1, R′ = CH3, Ph, p-C6H4CH3) react with alkynes (RCtriple bond; length of mdashCH; R = Ph, p-C6H4CH3) in the presence of NEt3 to give acyl-alkynyl-iridium Ir(C(double bond; length as m-dashO)CH3)(–Ctriple bond; length of mdashCR)(η2-O2CR′)(PPh3)2 (4) which further react with RCtriple bond; length of mdashCH to give alkyl-carbonyl-cis-bis(alkynyl) iridium Ir(CH3)(CO)(Ctriple bond; length of mdashCR)2(PPh3)2 (5). cis-Bis(alkenyl)iridium complexes, Ir(–CHdouble bond; length as m-dashCH2)2(η2-O2CCH3)(PPh3)2 (6) and (η2-O2CCH3)(PPh3)2 (7) react with substituted alkynes RCtriple bond; length of mdashCH (R = Ph, p-C6H4CH3, cyclohex-1-enyl) to give cis-bis(alkynyl) Ir(Ctriple bond; length of mdashCR)2(η2-O2CCH3)(PPh3)2 (9) that further react with RCtriple bond; length of mdashCH to undergo the alkyne insertion reaction into the Ir–O bond to produce iridacycles containing vinyl acetate ligands, (–Ctriple bond; length of mdashCR)2(PPh3)2 (8).