Formation of N-substituted 4- and 7-oxo-4,5,6,7-tetrahydroindoles revisited: a mechanistic interpretation and conversion into 4- and 7-oxoindoles

Autor: Sven M. Baum, Justin K. Cowell, Alexander McKillop, A. G. Montalban
Rok vydání: 2012
Předmět:
Zdroj: Tetrahedron Letters. 53:4276-4279
ISSN: 0040-4039
DOI: 10.1016/j.tetlet.2012.05.090
Popis: An efficient method for the preparation of 4-oxo-4,5,6,7-tetrahydroindoles was successfully applied to the synthesis of N-substituted 7-oxo-4,5,6,7-tetrahydroindoles for the first time. Both isomers where converted into their corresponding 4- and 7-oxoindoles in good yields utilizing a novel aromatization protocol. Based on the impurity profile obtained, however, different mechanisms for the formation of the 4- and 7-oxo-4,5,6,7-tetrahydroindole derivatives are discussed. In addition, the reaction sequences appear to be stereospecific allowing for the direct introduction of a chiral center α to the nitrogen and preparation of enantiomerically enriched products.
Databáze: OpenAIRE