Regioisomeric and substituent effects upon the outcome of the reaction of 1-borodienes with nitrosoarene compounds

Eberlin, Ludovic; Carboni, Bertrand; Whiting, Andrew

doi:10.1021/acs.joc.5b00593

Regioisomeric and substituent effects upon the outcome of the reaction of 1-borodienes with nitrosoarene compounds

Eberlin, Ludovic; Carboni, Bertrand; Whiting, Andrew

Authors

Ludovic Eberlin

Bertrand Carboni

Professor Andrew Whiting andy.whiting@durham.ac.uk
Emeritus Professor

Abstract

A study of the reactivity of 1-borodienes with nitrosoarene compounds has been carried out showing an outcome that differs according to the hybridization state of the boron moiety. Using an sp2 boron substituent, a one-pot hetero-Diels–Alder/ring contraction cascade occurred to afford N-arylpyrroles with low to good yields depending on the electronic properties of the substituents on the borodiene, whereas an sp3 boron substituent led to the formation of stable boro-oxazines with high regioselectivity in most of the cases, in moderate to good yields. 1H and 11B NMR studies on two boro-oxazine regioisomers showed that selective deprotection can be performed. Formation of either the pyrrole or the furan derivative is pH- and regioisomer-structure-dependent. The results obtained, together with previous B3LYP calculations, support mechanistic proposals which suggest that pyrrole, or furan, formation proceeds via oxazine formation, followed by a boryl rearrangement and an intramolecular addition–elimination sequence.

Citation

Eberlin, L., Carboni, B., & Whiting, A. (2015). Regioisomeric and substituent effects upon the outcome of the reaction of 1-borodienes with nitrosoarene compounds. Journal of Organic Chemistry, 80(13), 6574-6583. https://doi.org/10.1021/acs.joc.5b00593

Journal Article Type	Article
Acceptance Date	Jun 3, 2015
Online Publication Date	Jun 3, 2015
Publication Date	Jul 2, 2015
Deposit Date	Jun 12, 2015
Publicly Available Date	Jun 3, 2016
Journal	Journal of Organic Chemistry
Print ISSN	0022-3263
Electronic ISSN	1520-6904
Publisher	American Chemical Society
Peer Reviewed	Peer Reviewed
Volume	80
Issue	13
Pages	6574-6583
DOI	https://doi.org/10.1021/acs.joc.5b00593

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Copyright Statement
This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Organic Chemistry, copyright © 2015 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/acs.joc.5b00593.