Preparation of Heterocyclic Amines by an Oxidative Amination of Zinc Organometallics Mediated by Cu~(I): A New Oxidative Cycloamination for the Preparation of Annulated Indole Derivatives

摘要

Functionalized heterocyclic zinc reagents are easily aminated by an oxidative amination reaction of zinc amidocuprates prepared from various lithium amides. For the oxidation step, PhI(OAc)_(2) proved to be the best reagent. The required heterocyclic zinc organometallics can be prepared either by direct metalation, by magnesium insertion in the presence of ZnCl_(2), or by transmetalation of a suitable magnesium reagent. Furthermore, we report a new ring-closing reaction involving an intramolecular oxidative amination reaction. This reaction allows the preparation of tetracyclic heterocycles containing furan, thiophene, or indole rings.