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Asymmetric Fluorination of α-Branched Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer Catalysis and Enamine Catalysis using Protected Amino Acids
[Image: see text] We report a study involving the successful merger of two separate chiral catalytic cycles: a chiral anion phase-transfer catalysis cycle to activate Selectfluor and an enamine activation cycle, using a protected amino acid as organocatalyst. We have demonstrated the viability of th...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical
Society
2014
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4119784/ https://www.ncbi.nlm.nih.gov/pubmed/24684209 http://dx.doi.org/10.1021/ja500882x |
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author | Yang, Xiaoyu Phipps, Robert J. Toste, F. Dean |
author_facet | Yang, Xiaoyu Phipps, Robert J. Toste, F. Dean |
author_sort | Yang, Xiaoyu |
collection | PubMed |
description | [Image: see text] We report a study involving the successful merger of two separate chiral catalytic cycles: a chiral anion phase-transfer catalysis cycle to activate Selectfluor and an enamine activation cycle, using a protected amino acid as organocatalyst. We have demonstrated the viability of this approach with the direct asymmetric fluorination of α-substituted cyclohexanones to generate quaternary fluorine-containing stereocenters. With these two chiral catalytic cycles operating together in a matched sense, high enantioselectivites can be achieved, and we envisage that this dual catalysis method has the potential to be more broadly applicable, given the breadth of enamine catalysis. It also represents a rare example of chiral enamine catalysis operating successfully on α-branched ketones, substrates commonly inert to this activation mode. |
format | Online Article Text |
id | pubmed-4119784 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | American Chemical
Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-41197842015-03-31 Asymmetric Fluorination of α-Branched Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer Catalysis and Enamine Catalysis using Protected Amino Acids Yang, Xiaoyu Phipps, Robert J. Toste, F. Dean J Am Chem Soc [Image: see text] We report a study involving the successful merger of two separate chiral catalytic cycles: a chiral anion phase-transfer catalysis cycle to activate Selectfluor and an enamine activation cycle, using a protected amino acid as organocatalyst. We have demonstrated the viability of this approach with the direct asymmetric fluorination of α-substituted cyclohexanones to generate quaternary fluorine-containing stereocenters. With these two chiral catalytic cycles operating together in a matched sense, high enantioselectivites can be achieved, and we envisage that this dual catalysis method has the potential to be more broadly applicable, given the breadth of enamine catalysis. It also represents a rare example of chiral enamine catalysis operating successfully on α-branched ketones, substrates commonly inert to this activation mode. American Chemical Society 2014-03-31 2014-04-09 /pmc/articles/PMC4119784/ /pubmed/24684209 http://dx.doi.org/10.1021/ja500882x Text en Copyright © 2014 American Chemical Society Terms of Use (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) |
spellingShingle | Yang, Xiaoyu Phipps, Robert J. Toste, F. Dean Asymmetric Fluorination of α-Branched Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer Catalysis and Enamine Catalysis using Protected Amino Acids |
title | Asymmetric
Fluorination of α-Branched
Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer
Catalysis and Enamine Catalysis using Protected Amino Acids |
title_full | Asymmetric
Fluorination of α-Branched
Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer
Catalysis and Enamine Catalysis using Protected Amino Acids |
title_fullStr | Asymmetric
Fluorination of α-Branched
Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer
Catalysis and Enamine Catalysis using Protected Amino Acids |
title_full_unstemmed | Asymmetric
Fluorination of α-Branched
Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer
Catalysis and Enamine Catalysis using Protected Amino Acids |
title_short | Asymmetric
Fluorination of α-Branched
Cyclohexanones Enabled by a Combination of Chiral Anion Phase-Transfer
Catalysis and Enamine Catalysis using Protected Amino Acids |
title_sort | asymmetric
fluorination of α-branched
cyclohexanones enabled by a combination of chiral anion phase-transfer
catalysis and enamine catalysis using protected amino acids |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4119784/ https://www.ncbi.nlm.nih.gov/pubmed/24684209 http://dx.doi.org/10.1021/ja500882x |
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