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Regioselective Oxidative Ring Opening of Cyclopropyl Silyl Ethers: A Quantum Chemical Study |
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| Authors: | Heiko Rinderhagen Dr Jochen Mattay Prof Rafael Nussbaum Thomas Bally Prof |
| Institution: | 1. Department of Chemistry, Bielefeld University, P.O. Box 100131, 33501 Bielefeld (Germany);2. Present Address: CILAG AG, Hochstrasse 201, 8205 Schaffhausen (Switzerland);3. Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland) |
| Abstract: | In contrast to the structurally and configurationally stable alkyl‐ or aryl‐substituted cyclopropyl radical cations, cyclopropyl silyl ethers undergo spontaneous ring opening upon oxidation whereby the endocyclic C? C(O‐TMS) bond is cleaved with remarkable selectivity. DFT calculations on 1‐trimethylsilyloxybicyclo4.1.0]heptane show that this selectivity arises from the topology of the potential surface of the corresponding radical cation which is initially generated in a very steep region of the potential surface from where the steepest descent leads to cleavage of the endocyclic rather than the lateral C? C(OTMS) bond. Cleavage of the lateral bond leads to interesting conformational changes which are explored in detail. |
| Keywords: | cations cyclopropyl ethers electron transfer radicals potential surfaces |