Iron‐Catalyzed Oxidative C−C and N−N Coupling of Diarylamines and Synthesis of Spiroacridines

Abstract

AbstractWe describe iron‐catalyzed intermolecular oxidative coupling reactions of diarylamines to form substituted 2,2′‐bis(arylamino)biaryl compounds, tetraarylhydrazines, and 5,6‐dihydrobenzo[c]cinnolines with the same hexadecafluorinated iron–phthalocyanine catalyst. The mild formation of C−C or N−N bonds was controlled by the use of acidic or basic additives. In contrast to most iron‐catalyzed dehydrogenative coupling reactions, ambient air could be used as the sole oxidant. Moreover, iron(III) chloride hexahydrate promoted a one‐pot coupling and subsequent intramolecular dearomative coupling to give 10H‐spiro[acridine‐9,1′‐cyclohexa‐2′,5′‐dien‐4′‐ones].