ORGN 410 |
| Scott Gronert1, Adelaide Fagin1, Keiko Okamoto1, Lawrence M. Pratt2, and Sudha Mogali2. (1) Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, (2) Department of Chemistry, Fisk University, 1000 17th Ave. N, Nashville, TN 37211 |
| Ion trap mass spectrometry and ab initio calculations were used to examine the relative rates of the gas phase nucleophilic substitution and elimination reactions of alkyl halides. Rate constants and branching ratios were measured for the reaction of a benzoate nucleophile with ethyl, n-butyl, isopropyl, isobutyl, s-butyl, and t-butyl bromide and iodide. In addition, ab initio calculations (MP2/6-31+G**) using acetate as a model nucleophile were completed and activation barriers were determined. As expected, the SN2/E2 ratio dropped with increased branching on the alkyl halide (particularly at the a-carbon). In general, there is good correspondence between the experimental and computed data for the bromides, but it appears that the calculations systematically overestimate the barriers with the iodides. |
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Physical Organic, Materials, Heterocycles, Aromatics, Metal-Mediated Reactions
8:00 PM-10:00 PM, Tuesday, September 9, 2003 Hilton New York -- Americas Hall 1, Poster
Division of Organic Chemistry |