Thermally-Induced 1,2-Shifts To Convert Olefins to Carbenes: Does Silicon Do It? If So, Why Not Carbon? Barton, Thomas Lin, Jibing Ijadi-Maghsoodi, Sina Gordon, Mark Power, Martin Zhang, Xianping Ma, Zhongxin Shimizu, Hideaki Gordon, Mark
dc.contributor.department Ames Laboratory
dc.contributor.department Chemistry 2018-02-17T07:44:25.000 2020-06-30T01:19:07Z 2020-06-30T01:19:07Z Sun Jan 01 00:00:00 UTC 1995 1995-11-01
dc.description.abstract <p>Thermal isomerization of olefins to carbenes via a 1,2-silyl shift was examined by both experiment and theory. No evidence of this rearrangement was found for acyclic vinylsilanes, nor could electronic assistance by silicon be identified in cis, trans isomerizations. Serendipitous synthesis of a 2,4-dimethylene-1,3-disilacyclobutane allowed a kinetic examination of its gas-phase, thermal ring expansion to a 2-methylene-1,3-disilacyclopentene. The Arrhenius parameters (log A = 12.48, Eact = 54.09 kcallmol) are the first to be reported for an olefin-to-carbene rearrangement. The analogous all-carbon system failed to ring expand. Ab initio calculations revealed that this was opposite to any predictions which would be made from ring strain considerations. Calculations showed that for silyl migration the transition state was late and was actually the carbene, while for carbon migration the TS was early and considerably higher in energy than the resulting carbene. The 2-methylene-1-silacyclobutane rearrangement (ref 5) was reexamined to find that reversible ring opening to a 1,4-diradical occurred at temperatures below those required to ring expand via a carbene TS.</p>
dc.description.comments <p>Reprinted (adapted) with permission from <em>Journal of the American Chemical Society </em>117 (1995): 11695, doi:<a href="" target="_blank">10.1021/ja00152a010</a>. Copyright 1995 American Chemical Society.</p>
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dc.identifier.articleid 1289
dc.identifier.contextkey 7920504
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath chem_pubs/299
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 23:15:56 UTC 2022
dc.source.bitstream archive/|||Fri Jan 14 23:15:57 UTC 2022
dc.source.uri 10.1021/ja00152a010
dc.subject.disciplines Chemistry
dc.title Thermally-Induced 1,2-Shifts To Convert Olefins to Carbenes: Does Silicon Do It? If So, Why Not Carbon?
dc.type article
dc.type.genre article
dspace.entity.type Publication
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relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11
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