We describe a simple and efficient ruthenium-catalyzed reaction in which propargylic alcohol HCCC(Ph)2OH is split into carbon monoxide CO, formaldehyde H2CO and ketone (Ph)2CO via cleavage of carbon-carbon triple and single bonds. A plausible reaction mechanism is proposed on the basis of ruthenium vinyl and formyl intermediates We describe a simple and efficient ruthenium-catalyzed reaction in which propargylic alcohol HCαCβ-Cγ(R1R2)OH is split into carbon monoxide CαO, formaldehyde H2CβO and ketone (R1R2)CγO via cleavage of carbon-carbon triple and single bonds. A plausible reaction mechanism is proposed on the basis of ruthenium vinyl and formyl intermediates. Display omitted •We disclose the results of detailed catalytic and structural investigations on the reaction of propargylic alcohol with TpPPh3(HNCPh2)RuCl.•A number of new ruthenium complexes have been prepared.•A plausible reaction mechanism is proposed on the basis of ruthenium vinyl and formyl intermediates.•Their structures are elucidated by IR, NMR and X-ray crystallography.