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The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects
Density functional theory calculations demonstrate that the reversal of regiochemical outcome of the addition for substituted methyl propiolates in the rhodium-catalyzed [(2 + 2) + 2] carbocyclization with PPh(3) and (S)-xyl-binap as ligands is both electronically and sterically controlled. For exam...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5510011/ https://www.ncbi.nlm.nih.gov/pubmed/28757978 http://dx.doi.org/10.1039/c5sc02307f |
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author | Crandell, Douglas W. Mazumder, Shivnath Evans, P. Andrew Baik, Mu-Hyun |
author_facet | Crandell, Douglas W. Mazumder, Shivnath Evans, P. Andrew Baik, Mu-Hyun |
author_sort | Crandell, Douglas W. |
collection | PubMed |
description | Density functional theory calculations demonstrate that the reversal of regiochemical outcome of the addition for substituted methyl propiolates in the rhodium-catalyzed [(2 + 2) + 2] carbocyclization with PPh(3) and (S)-xyl-binap as ligands is both electronically and sterically controlled. For example, the ester functionality polarizes the alkyne π* orbital to favor overlap of the methyl-substituted terminus of the alkyne with the p(π)-orbital of the alkenyl fragment of the rhodacycle during alkyne insertion with PPh(3) as the ligand. In contrast, the sterically demanding xyl-binap ligand cannot accommodate the analogous alkyne orientation, thereby forcing insertion to occur at the sterically preferred ester terminus, overriding the electronically preferred orientation for alkyne insertion. |
format | Online Article Text |
id | pubmed-5510011 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-55100112017-07-28 The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects Crandell, Douglas W. Mazumder, Shivnath Evans, P. Andrew Baik, Mu-Hyun Chem Sci Chemistry Density functional theory calculations demonstrate that the reversal of regiochemical outcome of the addition for substituted methyl propiolates in the rhodium-catalyzed [(2 + 2) + 2] carbocyclization with PPh(3) and (S)-xyl-binap as ligands is both electronically and sterically controlled. For example, the ester functionality polarizes the alkyne π* orbital to favor overlap of the methyl-substituted terminus of the alkyne with the p(π)-orbital of the alkenyl fragment of the rhodacycle during alkyne insertion with PPh(3) as the ligand. In contrast, the sterically demanding xyl-binap ligand cannot accommodate the analogous alkyne orientation, thereby forcing insertion to occur at the sterically preferred ester terminus, overriding the electronically preferred orientation for alkyne insertion. Royal Society of Chemistry 2015-12-01 2015-08-25 /pmc/articles/PMC5510011/ /pubmed/28757978 http://dx.doi.org/10.1039/c5sc02307f Text en This journal is © The Royal Society of Chemistry 2015 http://creativecommons.org/licenses/by/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License (http://creativecommons.org/licenses/by/3.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Chemistry Crandell, Douglas W. Mazumder, Shivnath Evans, P. Andrew Baik, Mu-Hyun The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects |
title | The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects
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title_full | The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects
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title_fullStr | The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects
|
title_full_unstemmed | The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects
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title_short | The origin of the ligand-controlled regioselectivity in Rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects
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title_sort | origin of the ligand-controlled regioselectivity in rh-catalyzed [(2 + 2) + 2] carbocyclizations: steric vs. stereoelectronic effects |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5510011/ https://www.ncbi.nlm.nih.gov/pubmed/28757978 http://dx.doi.org/10.1039/c5sc02307f |
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