A stereoselective intramolecular retro-ene reaction catalysed by aluminium chloride

Article abstract of DOI:10.1016/S0040-4039(97)00404-8

Reaction of 5-(2-naphthalenol)-1-pentenes with I(III) reagents results in nuclcophilic substitution at C-1 rather than [4+2] intramolecular ionic cycloaddition of the proposed intermediate arenoxenium cations. Treatment of the same precursors with aluminium chloride results in a stereoselective intramolecular cyclisation to spiroketones. Evidence that the mechanism of formation involves a cyclic aluminium intermediate is presented.