Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence

[Image: see text] Coupling reactions between benzylamines and boronic esters have been investigated. ortho-Lithiated benzylamines react with boronic esters and a N-activator to afford ortho-substituted benzylic boronic esters with formal 1,1′-benzylidene insertion into the C–B bond. The reaction occ...

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Autores principales: Aichhorn, Stefan, Bigler, Raphael, Myers, Eddie L., Aggarwal, Varinder K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2017
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5520102/
https://www.ncbi.nlm.nih.gov/pubmed/28661133
http://dx.doi.org/10.1021/jacs.7b05880
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author Aichhorn, Stefan
Bigler, Raphael
Myers, Eddie L.
Aggarwal, Varinder K.
author_facet Aichhorn, Stefan
Bigler, Raphael
Myers, Eddie L.
Aggarwal, Varinder K.
author_sort Aichhorn, Stefan
collection PubMed
description [Image: see text] Coupling reactions between benzylamines and boronic esters have been investigated. ortho-Lithiated benzylamines react with boronic esters and a N-activator to afford ortho-substituted benzylic boronic esters with formal 1,1′-benzylidene insertion into the C–B bond. The reaction occurs by a S(N)2′ elimination and 1,2-metalate rearrangement of the N-activated boronate complex to afford a dearomatized intermediate, which undergoes a Lewis-acid catalyzed 1,3-borotropic shift to afford the boronic ester products in high yield and with excellent enantiospecificity. The use of enantioenriched α-substituted benzylamines gave the corresponding secondary boronic esters with high ee.
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spelling pubmed-55201022017-07-24 Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence Aichhorn, Stefan Bigler, Raphael Myers, Eddie L. Aggarwal, Varinder K. J Am Chem Soc [Image: see text] Coupling reactions between benzylamines and boronic esters have been investigated. ortho-Lithiated benzylamines react with boronic esters and a N-activator to afford ortho-substituted benzylic boronic esters with formal 1,1′-benzylidene insertion into the C–B bond. The reaction occurs by a S(N)2′ elimination and 1,2-metalate rearrangement of the N-activated boronate complex to afford a dearomatized intermediate, which undergoes a Lewis-acid catalyzed 1,3-borotropic shift to afford the boronic ester products in high yield and with excellent enantiospecificity. The use of enantioenriched α-substituted benzylamines gave the corresponding secondary boronic esters with high ee. American Chemical Society 2017-06-29 2017-07-19 /pmc/articles/PMC5520102/ /pubmed/28661133 http://dx.doi.org/10.1021/jacs.7b05880 Text en Copyright © 2017 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
spellingShingle Aichhorn, Stefan
Bigler, Raphael
Myers, Eddie L.
Aggarwal, Varinder K.
Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
title Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
title_full Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
title_fullStr Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
title_full_unstemmed Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
title_short Enantiospecific Synthesis of ortho-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
title_sort enantiospecific synthesis of ortho-substituted benzylic boronic esters by a 1,2-metalate rearrangement/1,3-borotropic shift sequence
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5520102/
https://www.ncbi.nlm.nih.gov/pubmed/28661133
http://dx.doi.org/10.1021/jacs.7b05880
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