Steven W. Szczepanski

Unusual regiochemistry in a beckmann-like rearrangement of camphor. α-Camphidone via methylene migration.

Abstract Reaction of camphor with hydroxylamine-O-sulfonic acid affords the nitrogen insertion product α-camphidone by migration of the methylene group rather than the bridgehead. Since Beckmann rearrangements of trigonal oximes afford bridgehead cleavage products with camphor, an alternative synchronous rearrangement of a tetrahedral intermediate is proposed for this Beckmann-like reaction.

Heterodienophiles. 10. Stereoselectivity in the 1,4-cycloaddition of N-(ethoxycarbonyl)-C-alkylaldiminium ions with 1,3-cyclohexadiene

Stereochimie de la reaction alkylidene bis-carbamates avec le cyclohexadiene-1,3 en presence de trifluoroborane

Azatricycles from substituted pyridines. Synthesis and rearrangement of N-ethoxycarbonyl-2-azatricyclo[4.3.1.03,7]dec-8-enes.

Abstract The scope and relative rates of intramolecular cycloaddition reactions of methyl-substituted 2-[3-butenyl]-1,2-dihydropyridines 4 have been studied. Cycloadducts 5 can be rearranged to 14 upon reaction with bromine, except when olefinic methyl groups are present.

Regioselective Synthesis of 4-, 5-, and 6-Alkyl and Dialkyl 5,6-Dehydroisoquinuclidines from Phenylvinylsulfone Cycloadducts of N-Ethoxycarbonyl-1,2-Dihydropyridines

Abstract A regioselective route to 4-, 5-, and 6-alkyl or 4,5-, 4,6-, and 5,6-dialkyl-5,6-dehydroisoquinuclidines 1a-f is described.

Relative diels-alder reactivity of 3-alkyl-2-(3-butenyl)-1,2-dihydropyridines. : Interplay of electronic and steric factors related to the 3-alkyl group.

Abstract Steric effects have been found to predominate over Frontier Molecular Orbital (FMO) effects in controlling the relative rates of intramolecular cycloadditions of 3-R-substituted- 2-(3-butenyl)1,2-dihydropyridines (DHP) in the series 4a–c (R = H, Me, Et).