Indenols, indenones and (arylcyclohexadienyl)Mn(CO)3 π-complexes from the thermally promoted reactions of alkynes with ortho-Mn(CO)4 aryl ketone, amide, ester and aldehyde derivatives

Alkynes normally react with orthomanganated aryl ketones to give 1H-inden-1-ols and with other orthomanganated arylcarbonyl compounds to give related cyclopentaannulation products, but in some cases triple alkyne insertion leads to (cyclohexadienyl)Mn(CO)3 complexes; the crystal structure of [(1,2,3,4,5-η)-2-(3-acetylthien-2-yl)-1,3,5-triphenylcyclohexadienyl]tricarbonylmanganese is reported.