Manganese carbonyl-mediated reactions of azabutadienes with phenylacetylene, methyl acrylate and other unsaturated molecules

Reaction of PhCH2Mn(CO)5 with l,4-di-aryl-1-aza-1,3-butadienes gave substituted pyrrolinonyl rings which were η4-coordinated to a Mn(CO)3 group. These are formed by intramolecular CO insertion into a (non-isolated) cyclomanganated intermediate, followed by cyclisation. Other unsaturated reagents (PhCtriple bond; length of mdashCH, CH2double bond; length as m-dashCHCOOMe, PhNCO) gave products arising from insertion of these, including a structurally characterised tri-aryl-η5-azacyclohexadienyl-Mn(CO)3 complex from the reaction with the alkyne.