TBHP-promoted sequential carboxamidation and aromatisation of aryl isonitriles with formamides†
Abstract
The tert-butyl hydroperoxide (TBHP)-promoted sequential carboxamidation and aromatisation of isonitriles with formamides was developed. This procedure tolerates a series of functional groups, such as methyl, fluoro, chloro, acetyl, methoxy carbonyl and cyano. This reaction involved the addition of formamide radicals to isonitriles and sequential C–C bond formation by intramolecular aromatic cyclisation, leading to phenanthridine 6-carboxamides in moderate to good yields.