The reaction of benzonorbornadiene and related compounds with iron carbonyls

Abstract

Reaction of benzonorbornadiene, 7-isopropylidenebenzonorbornadiene (1,4-dihydro-9-isopropylidene-1,4-methanonaphthalene) and 1,4-dihydro-1,4-epoxynaphthalene (7-oxabenzonorbornadiene) with dicarbonyldinitrosyliron, Fe(CO)₂(NO)₂, gave in good yields the corresponding dimers having the exo-trans-exo configuration. Treatment of a mixture of benzonorbornadiene and norbornadiene with Fe(CO)₂(NO)₂ gave a 'crossed dimer', in addition to the dimers derived from benzonorbornadiene and norbornadiene. The reaction of benzonorbornadiene with pentacarbonyliron at 100º gave the exo-trans-exo dimer and a ketone derived by dimerization and carbonyl insertion. This ketone, and the analogous ketone obtained from 7-isopropylidenebenzonorbornadiene, have been assigned the exo-trans-exo configuration. Reaction of 1,4-dihydro-1,4-epoxynaphthalene with enneacarbonyldiiron, Fe₂(CO)₉, at room temperature gave tetracarbonyl(l,4-dihydro-l,4-epoxynaphthalene)iron(0), in which the olefinic ח-bond is bonded to the metal. In solution at 63º this complex gave naphthalene.