Metal-Free, Regioselective, Dehydrogenative Cross-Coupling between Formamides/Aldehydes and Coumarins by C-H Functionalization
作者:Mohit Gupta、Prashant Kumar、Vijay Bahadur、Krishan Kumar、Virinder S. Parmar、Brajendra K. Singh
DOI:10.1002/ejoc.201701764
日期:2018.2.21
A general methodology for the regioselective C‐3 functionalization of coumarins and azacoumarins by using formamides and aldehydes has been achieved in a single step with tert‐butyl peroxybenzoate as a radical initiator. This methodology provides a convenient and cost‐effective route to the products under metal‐free conditions with excellent regioselectivity and wide substrate scope.
Diels-Alder cycloadditions of 2(1H)-quinolones having an electron-withdrawing group at the 3-position with alkyl- and silyloxy-1, 3-butadienes (2a, b) were carried out to give phenanthridones richly functionalized regio- or stereoselectively under conditions of atmospheric and high pressure. Furthermore, regioselectivity and chemoselectivity of 3-substituted 2(1H)-quinolones to 2a, b were examined using MO calculation.