Photochemical generation and chemistry of α-Acetoxycarbene

Jonathan Mann, Colby College

Document Type Honors Thesis (Open Access)


Efforts have been made at generating the parent α-acetoxycarbene from a non-nitrogenous precursor. Baeyer-Villiger oxidation of the ketone, 1-(1a,9b-dihydro-lHcyclopropa[1] phenanthren-1-yl)-ethanone, available in two steps from phenanthrene, led to the ester, 1-(1 a,9b-dihydro-lH-cyclopropa[/]phenanthren-l-yl)-acetate, which is a photochemical precursor of the parent α-acetoxycarbene intermediate. Photolysis of the ester in cyclohexene afforded an isomeric mixture of endo and exo acetates resulting from the carbene adding to the π-bond. Photolysis of the ester in trans-3-hexene yielded a single trans-cis acetate, a product of the same cycloaddition process. The formation of methyl glyoxal, via the l,2-acyl shift of the carbene, is observed through its derivatives. Energy minimizations at the B3LYP/6-31G* level of theory located a singlet minimum that is significantly lower in energy than the corresponding triplet.