Accession Number:

AD0617989

Title:

ELECTRONIC EFFECTS IN E2 REACTIONS. II. T-BUTOXIDE-INDUCED ELIMINATIONS OF 2-METHYL3-PENTYL ARENESULFONATES,

Descriptive Note:

Corporate Author:

CARNEGIE INST OF TECH PITTSBURGH PA

Personal Author(s):

Report Date:

1964-11-13

Pagination or Media Count:

12.0

Abstract:

As part of a study of the influence of electronic effects imposed by the leaving group on orientation in E2 reactions, a study of elimination in a series of 2-methyl-3-pentyl arenesulfonates was carried out. The compositions of the olefin mixtures resulting from reaction of selected members of this series with potassium t-butoxide in t-butanol, 50 by volume t-butanol-dioxane, 25 by volume t-butanol-dioxane, and 25 by volume t-butanol-dimethyl sulfoxide, at 50C, were determined using vapor phase chromatography. Second-order rate constants were measured for these reactions in t-butanol, and 50 t-butanoldioxane at 50C and in 25 t-butanol-dimethyl sulfoxide at 25C. The compositions of the olefin mixtures vary in a fairly regular way with changes in the electronic nature of the leaving group, the fraction of 2-methyl-2-pentene and ratio of trans- to cis-4-methyl-2-pentene for the most part increasing with increasing electron withdrawal. The E2 reactions in 25 t-butanol-dimethyl sulfoxide produce trans- and cis-4-methyl-2-pentene in ratios 20 to 35 considerably higher than those in an equilibrium mixture ca. 6. The results are discussed in terms of recent views on the E2 transition state. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE