NH2 as a directing group: from the unexpected cyclopalladation of aminoesters to the preparation of benzolactams by Pd(II)-catalyzed carbonylation of N-unprotected arylethylamines
An unusual NH2-directed Pd(II)-catalytic carbonylation of quaternary aromatic α-amino esters to yield benzolactams has been developed. The steric hindrance around the amino group is pivotal for the success of the process. The stoichiometric cyclometallation of a variety amino esters has been studied...
| Autores: | , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2013 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/43589 |
| Acceso en línea: | https://hdl.handle.net/2445/43589 |
| Access Level: | acceso abierto |
| Palabra clave: | Pal·ladi (Element químic) Cinètica química Compostos organometàl·lics Cristal·lografia Catàlisi Palladium Chemical kinetics Organometallic compounds Crystallography Catalysis |
| Sumario: | An unusual NH2-directed Pd(II)-catalytic carbonylation of quaternary aromatic α-amino esters to yield benzolactams has been developed. The steric hindrance around the amino group is pivotal for the success of the process. The stoichiometric cyclometallation of a variety amino esters has been studied in order to evaluate the influence of the different variables (size of the metallacycle, aromatic ring substituents, and steric bulk) in the process, and a complete kinetico-mechanistic study of the cyclopalladation process has been carried out. The experimental results indicate that the full substitution of the carbon in the α position of the amino esters plays an important role in their cyclopalladation reaction. The reaction shows a strong bias to 6-membered lactams over the 5-membered analogues, which can be explained by a greater reactivity of the six-membered palladacycles. |
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