Synthesis of α,ß-Unsaturated N-Aryl Ketonitrones from Oximes and Diaryliodonium Salts: Observation of a Metal-Free N-Arylation Process.

An efficient transition-metal-free method for the preparation of α,ß-unsaturated N-aryl ketonitrones under mild conditions has been developed. This reaction shows good functional group tolerance for both electron-rich and electron-deficient substituents on both oximes and diaryliodonium salts. Two examples of gram-scale preparations have been realized in good yields. Further transformations of these nitrones to different N-heterocycles have been demonstrated. DFT calculations suggest that N-arylation products are formed by [1,3]-phenyl migration of an O-coordinated oximate complex via a four-centered transition state, while the O-arylation products are formed by [1,3]-phenyl migration of a N-coordinated oximate complex.

Synthesis of 2-Aminobenzonitriles through Nitrosation Reaction and Sequential Iron(III)-Catalyzed C-C Bond Cleavage of 2-Arylindoles.

A variety of 2-aminobenzonitriles were prepared from 2-arylindoles in good to excellent yields through tert-butylnitrite (TBN)-mediated nitrosation and sequential iron(III)-catalyzed C-C Bond cleavage in a one-pot fashion. The 2-aminobenzonitriles can be used to rapidly synthesize benzoxazinones by intramolecular condensation. The present method features an inexpensive iron(III) catalyst, gram scalable preparations, and novel C-C bond cleavage of indoles.