A direct copper-catalyzed route to pyrrolo-fused heterocycles from boronic acids
作者:Ramsay E. Beveridge、Brian S. Gerstenberger
DOI:10.1016/j.tetlet.2011.11.091
日期:2012.2
related pyrrolo-fused heterocycles from boronic acids, DBAD (di-tert-butyl-diazodicarboxylate) and enolizable aldehydes and ketones is presented. The reaction proceeds via a one-pot four-step cascade sequence with key steps involving a copper-catalyzed boronic acid coupling to DBAD and a Fischer indolization providing access to a variety of pharmaceutically interesting heterocycles including pyrrolo-pyridines
Contrary to the common idea that Fischer indole cyclization often cannot be effectively applied to the synthesis of the corresponding azaindoles, we show that this approach can be actually very efficient for the formation of 4- and 6-azaindoles bearing an electron-donating group on the starting pyridylhydrazines. Two 4-azaindole natural product analogues were synthesized in a few steps and very good