Reaction of tricarbonyl(2–6-η-hexadienium)iron with amines, triphenyl-phosphine, and triphenylarsine: a method for the preparation of triene complexes

Abstract

Aniline and diphenylamine add to the substituted end of the diene in tricarbonyl(2–6-η-hexadienium)iron to give dienylamine complexes having syn geometry. Tertiary amines, PPh₃, and AsPh₃ add to the unsubstituted end to give quaternary adducts having anti geometry. The tertiary amine adducts undergo elimination when heated in vacuo to give the syn-hexatriene complex in good yield. Tricarbonyl(2–6-η-heptadienium)iron is converted directly into the syn-heptatriene complex on treatment with tertiary amines, but forms anti adducts with PPh₃. Hydrogen-2 labelled syn-[Fe(hexatriene)(CO)₃] protonates at its unto-ordinated double bond.