ORGN 400 |
| β-Silyl groups are known to stabilize carbocations, leading to rate enhancements in solvolytic reactions of up to 1012. In an attempt to thwart the tremendous stabilizing power of the β-silyl group, we have investigated carbocations in which geometric constraints greatly reduce overlap between the cationic orbital and the adjacent carbon-silicon bond. Syntheses and solvolytic studies of the substrates shown below will be presented. Results indicate a significant reduction in β-silicon stabilization of the carbocationic intermediates. In the case of 4, the β-silicon effect is nearly eliminated. Product studies also indicate that no TMS elimination occurs in 4. The major products arise from a ring-opened carbocation. Some ring-closed products derived from solvent capture were also observed.
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High Energy Species
8:00 AM-11:40 AM, Tuesday, August 21, 2007 BCEC -- 254 A/B, Oral
Division of Organic Chemistry |
