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Full-Text Articles in Physical Sciences and Mathematics
Photochemical Generation Of 2-Methoxy-2methylpropylidene And Its Rearrangement Pathways, Stanislav Presolski
Photochemical Generation Of 2-Methoxy-2methylpropylidene And Its Rearrangement Pathways, Stanislav Presolski
Honors Theses
2-methoxy-2-methylpropylidene was photochemically generated from a non-nitrogenous precursor, 1a,9b-Dihydro-IH-cyclopropa[1]phenanthrene-l-etbane 2-methoxy-2-methyl, available in two steps from phenanthrene. Two competing rearrangement pathways were observed for the p-methoxy carbene, 1,2-methyl shift and C-H insertion, which had varying weights depending on the solvent used. Nevertheless, the C-H insertion was always predominant, contrary to the current understanding of B-substituted carbenes, which apparently needs revision. An attempt was also made to measure by LFP the rate constant of rearrangement and lifetime of the stabilized l-chloro-2-methoxy-2-metbylpropylidene.
Photochemical Generation And Chemistry Of Α-Acetoxycarbene, Jonathan Mann
Photochemical Generation And Chemistry Of Α-Acetoxycarbene, Jonathan Mann
Honors Theses
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 α-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. …
Photochemical Generation And Intramolecular Chemistry Of 2-Hydroxy-2-Methylpropylidene, Robin Farlow
Photochemical Generation And Intramolecular Chemistry Of 2-Hydroxy-2-Methylpropylidene, Robin Farlow
Honors Theses
2-(1a,9b-Dihydro-lH-cyclopropa[l]phenanthren-1-yl)-propan-2-ol was synthesized by two different but related synthetic routes and characterized by melting point, IR GC/MS, CHN, and NMR spectroscopy. Photolysis of the alcohol in benzene d-6 led to the formation of 2-butanone, 1-methylcyclopropanol, and 2,2-dimethyloxirane in a 26:10:1 ratio via 2-hydroxy-2methylpropylidene, a novel ?-hydroxycarbene. These products are a consequence of intramolecular insertions of the carbene into C-C, C-H, and O-H bonds. Molecular orbital calculations performed at the Becke-3LYP/6-31G(d) level indicate that the singlet form of this carbene is more thermodynamically stable than the triplet. Furthermore, the transition states to the three products from the singlet species were modeled …