A 4-tert-butyl-phenyl substituted (R)-[H8]-BINOL chiral calcium phosphate catalyzed enantioselective amination of 3-aryl-2-benzofuranones with dibenzyl azodicarboxylate is described. The catalyst loading of the reaction is 1 mol %. This transformation is facile and has a high degree atom economy, which gave products with good yields and high enantioselectivities (79% to 99%). This reaction has excellent ee and a broad substrate scope with mild reaction conditions.

A transition-metal-free, K2S2O8-mediated intramolecular oxidative nitrogenation/oxygenation of C(sp(3))-H in N-aryl benzylic amines followed by oxidation at the benzylic center has been developed for the synthesis of benzamidine/benzoxazine heterocycles, providing an expedient access to quinazolin-4(3H)-ones, N-aryl-2-arylbenzimidazoles, and 4H-3,1-benzoxazin-4-ones. A considerable amount of work dealing with the mechanistic study to understand the crucial intramolecular cyclization step largely favors an iminium ion as the key intermediate.

A unified approach to the tandem preparation of diverse nitrogen heterocycles via decarboxylative acylation of ortho-substituted amines with α-oxocarboxylic acids and subsequent intramolecular cyclizations has been developed. The key features of this work include: the first example of transition-metal-free decarboxylative amidation of α-oxocarboxylic acids with ortho-substituted amines, realization of intramolecular cyclization of amides employing nucleophiles that have previously been unexplored, mechanistic investigation of an unprecedented K2S2O8 promoted amide formation and its subsequent intramolecular cyclizations, and application to the synthesis of a best-selling marketed drug.

An exploration of a tandem approach to the sustainable synthesis of N-heterocycles from readily available N-aryl benzylamines or imines and ortho-substituted anilines is described, which demonstrates, for the first time, an important synthetic application of dynamic imine chemistry. The key features to the successful development of this protocol include the utilisation of N-aryl benzylamines as imine precursors in transimination, the occurrence of transimination in acetonitrile in the absence of any catalysts, an intramolecular nucleophilic addition occurring in the newly formed imine causing irreversible transimination, and the tandem event occurring under green conditions.

Domino reactions for the synthesis of phenazines have been developed that start from 1,2‐diaminoarenes and 1,2‐dihaloarenes and proceed through palladium‐catalyzed double N‐arylations (inter‐ and intramolecular) followed by an in situ oxidation. A variety of functional groups, which include base‐sensitive groups, were well tolerated under the optimized reaction conditions to afford phenazines in good to excellent yields. The protocol was extended to the synthesis of pyridoquinoxalines by employing either o‐phenylenediamines and 2,3‐dihalopyridines or 1,2‐diaminopyridines and 1,2‐dihaloarenes.