Date of Award


Document Type

Honors Thesis (Colby Access Only)


Colby College. Chemistry Dept.


Dasan M. Thamattoor

Second Advisor

Bradford P. Mundy


The photolytic precursor to, acetic acid 1a,9b-dibydro-1H- cyclopropa[1]phenanthren-l-yl methyl ester, was prepared in two steps from phenanthrene. Photolysis of the precursor generated β-acetoxycarbene, an intermediate, which rearranged to vinyl acetate in a yield of 18%. Conspicuously absent in the reaction mixture is γ•butyrolactone, a product that could have arisen via an intramolecular C-H insertion to seal the ring. Three intramolecular mechanisms were considered to account for the formation of vinyl acetate from the carbene. Deuterium labeling of the methylene group of the carbene was used to demonstrate that a simple 1;1- H shift was the principle mode of rearrangement, accounting for 82% of the vinyl acetate. Most interesting, however, is that the remaining vinyl acetate appears to arise from other mechanisms. Computational studies (B3LYP/6-31 G*) found a triplet minimum and two slightly less stable singlet minima for the carbene. The l,2-H shift was found to have an especially low barrier in two separate theoretical investigations.


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Carbenes, Photochemistry, ?-acetoxycarbene, rearrangement mode