CYCLOPROPANOL FORMATION VIA β-HYDROGEN ATOM ABSTRACTION: THE FIVE MEMBERED TRANSITION STATE ANALOGUE OF THE NORRISH TYPE II REACTION

Article abstract of DOI:10.1016/S0040-4039(00)84100-3

Solution phase photolysis of the Diels-Alder adduct 3 formed between o-quinodimethane and 2,3-dimethyl-1,4-naphthoquinone affords, via β-hydrogen atom abstraction and closure of the resulting 1,3-biradical, the cyclopropanol 4.The cyclopropanol itself undergoes secondary photolysis initiated by a novel ring opening process.Irradiation of crystals of adduct 3 affords no detectable photoproducts.The crystal and molecular structure of 3 reveals that cyclopropanol formation in the solid state would involve prohibitive non-bonded steric interactions between lattice neighbors.