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Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts

While the dearomatization of indoles by carbon–boron bond forming reactions is new and quite promising, they are so far mainly metal-catalyzed. Here, we establish the use of metal-free catalysts in promoting such reactions in an atom-efficient way. The in situ generated ambiphilic aminoborane cataly...

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Autores principales: Jayaraman, Arumugam, Misal Castro, Luis C., Desrosiers, Vincent, Fontaine, Frédéric-Georges
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5994747/
https://www.ncbi.nlm.nih.gov/pubmed/29938036
http://dx.doi.org/10.1039/c8sc01093e
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author Jayaraman, Arumugam
Misal Castro, Luis C.
Desrosiers, Vincent
Fontaine, Frédéric-Georges
author_facet Jayaraman, Arumugam
Misal Castro, Luis C.
Desrosiers, Vincent
Fontaine, Frédéric-Georges
author_sort Jayaraman, Arumugam
collection PubMed
description While the dearomatization of indoles by carbon–boron bond forming reactions is new and quite promising, they are so far mainly metal-catalyzed. Here, we establish the use of metal-free catalysts in promoting such reactions in an atom-efficient way. The in situ generated ambiphilic aminoborane catalyst (1-Pip-2-BH(2)-C(6)H(4))(2) (Pip = piperidyl) promotes borylative dearomatization of various 1-arylsulfonyl indoles with pinacolborane in a syn addition fashion, with H and Bpin groups added respectively to the 2 and 3 positions of indoles. Catalysis proceeds with good to excellent conversion and essentially with complete regio- and diastereoselectivity. From mechanistic insights and DFT computations, we realized and established that prototypical boranes can also catalyze this borylative dearomatization.
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spelling pubmed-59947472018-06-22 Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts Jayaraman, Arumugam Misal Castro, Luis C. Desrosiers, Vincent Fontaine, Frédéric-Georges Chem Sci Chemistry While the dearomatization of indoles by carbon–boron bond forming reactions is new and quite promising, they are so far mainly metal-catalyzed. Here, we establish the use of metal-free catalysts in promoting such reactions in an atom-efficient way. The in situ generated ambiphilic aminoborane catalyst (1-Pip-2-BH(2)-C(6)H(4))(2) (Pip = piperidyl) promotes borylative dearomatization of various 1-arylsulfonyl indoles with pinacolborane in a syn addition fashion, with H and Bpin groups added respectively to the 2 and 3 positions of indoles. Catalysis proceeds with good to excellent conversion and essentially with complete regio- and diastereoselectivity. From mechanistic insights and DFT computations, we realized and established that prototypical boranes can also catalyze this borylative dearomatization. Royal Society of Chemistry 2018-05-07 /pmc/articles/PMC5994747/ /pubmed/29938036 http://dx.doi.org/10.1039/c8sc01093e Text en This journal is © The Royal Society of Chemistry 2018 http://creativecommons.org/licenses/by-nc/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported Licence (CC BY-NC 3.0)
spellingShingle Chemistry
Jayaraman, Arumugam
Misal Castro, Luis C.
Desrosiers, Vincent
Fontaine, Frédéric-Georges
Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts
title Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts
title_full Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts
title_fullStr Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts
title_full_unstemmed Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts
title_short Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts
title_sort metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane c–h borylation catalysts
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5994747/
https://www.ncbi.nlm.nih.gov/pubmed/29938036
http://dx.doi.org/10.1039/c8sc01093e
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