Intermolecular and regioselective access to polysubstituted benzo- and dihydrobenzo[c]azepine derivatives: Modulating the reactivity of group 6 non-heteroatom-stabilized alkynyl carbene complexes
- González, Jairo. 2
- Gõmez, Aránzazu. 2
- Funes-Ardoiz, I. 1
- Santamaría, J. 2
- Sampedro, D. 1
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1
Universidad de La Rioja
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2
Universidad de Oviedo
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ISSN: 0947-6539
Année de publication: 2014
Volumen: 20
Número: 23
Pages: 7061-7068
Type: Article
D'autres publications dans: Chemistry - A European Journal
Objectifs de Développement Durable
Résumé
We highlight the versatility of non-heteroatom-stabilized tungsten-carbene complexes 3 synthesized in situ, which have been used in a modular approach to access 2-benzazepinium isolable intermediates 5. By employing very mild conditions, benzazepinium derivatives 5 have been obtained in high yield from simple compounds, such as acetylides 2, Fischer-type alkoxycarbenes 1, and phenylimines 4. The process, involving a formal [4+3] heterocycloaddition, occurs in a totally regioselective manner, which differs from the approach previously observed in similar procedures for other carbene analogues. This work, which involves three components, reveals a control of the reactivity of non-heteroatom-stabilized carbene complexes 3 ([4+3] vs. [2+2]- heterocycloaddition reactions) depending on the acetylide substitution pattern. The influence of the substitution pattern in the behavior of the complexes has been computationally analyzed and rationalized. Finally, elaboration of the 2-benzazepinium intermediates allows access to 3H-benzo[c]azepines 6 and 3H-1,2-dihydrobenzo[c]azepines 7-9 with high control of the substitution of the nine positions of the heterocycle. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.