Scope of Successive C-H Functionalizations of the Methyl Group in 3-Picolines: Intramolecular Carbonylation of Arenes to the Metal-Free Synthesis of 4-Azafluorenones

Org Lett. 2015 Dec 4;17(23):5890-3. doi: 10.1021/acs.orglett.5b03071. Epub 2015 Nov 20.

Abstract

A transition-metal-free, t-BuOOH mediated intramolecular carbonylation of arenes in 2-aryl-3-picolines via oxidative C-H functionalizations of the methyl group has been developed, providing an expedient synthesis of 4-azafluorenones. Distinct from the current literature wherein methylarenes have been used as acylating agents, 2-aryl-3-picolines in this study are transformed into aldehydes, which give 4-azafluorenones upon rapid intramolecular acylation. The study demonstrates the first example of intramolecular carbonylation of arenes utilizing a methyl group as latent carbonyl functionality.

Publication types

  • Research Support, Non-U.S. Gov't