Reactions of Cp*RhCl 2(PPh 3) ( 1) with 1-alkyne and H 2O in the presence of KPF 6 generated alkenyl ketone complexes [Cp*Rh( CR CHC OCH 2R)(PPh 3)](PF 6) ( 2) (R = Ph ( a), C 6H 4− p-Me ( b), C 6H 4- p-COOMe ( c), C 6H 4- p-NO 2 ( d)). A similar complex [Cp*Rh( CPh CHC OCH 2Ph)(PMePh 2)](PF 6) ( 2e) was obtained by use of Cp*RhCl 2(PMePh 2). It was revealed by X-ray analyses of 2b, 2c and 2e that the complexes 2 consist of the five-membered ring structures bound by the carbon and oxygen atoms of the alkenyl ketone group. Similar reactions of Cp*IrCl 2(PPh 3) ( 6) or (C 6Me 6)RuCl 2(PPh 3) ( 7) proceeded with a cleavage of C–C triple bond of 1-alkyne without formation of an alkenyl ketone complex, affording the corresponding carbonyl complexes, [Cp*IrCl(PPh 3)(CO)](PF 6) ( 8) or [(C 6Me 6)RuCl(PPh 3)(CO)](PF 6) ( 9). The diphosphine complexes [(Cp*MCl 2) 2{μ-diphos}] ( 4: M = Rh, diphos = dppm,; 12a: M = Ir, diphos = dppm; 12b: M = Ir, diphos = dppb) gave a Cl-bridged rhodium complex [{Cp*Rh(μ-Cl)} 2{μ-dppm}](PF 6) 2 ( 5), mono-carbonyl or dicarbonyl iridium complexes,[(Cp*IrCl 2){μ-dppm}{Cp*IrCl(CO)}](PF 6)( 13a) or [{Cp*IrCl(CO)} 2{μ-dppb}](PF 6) 2 ( 14b), respectively.