Formation of Arenes by Aromatization

Abstract

Dehydrogenation Elimination Reductive Elimination Rearrangement Cyclization and Annulation Diels–Alder and Related Reactions

Palladium-Catalyzed Aerobic Benzannulation of Amines, Benzaldehydes, and β-Dicarbonyls

“…While in recent years great progress has been made on the transition-metal-catalyzed direct arene C–H activation, the formation of substituted benzenes via annulations mainly relies on Diels–Alder-based transformation and [2 + 2 + 2] cyclotrimerization and annulations of unsaturated substrates such as alkynes, alkenes, , and enol ethers, among others . Alternatively, oxidative dehydrogenative aromatization of cyclohexenes and cyclohexanones also provides a convergent access to some well-decorated benzenes such as phenols and anilines . In spite of these utilities, the facile and novel construction of benzene rings starting from easily accessible raw materials is still highly desirable.…”

Pd/TiO2-Photocatalyzed Self-Condensation of Primary Amines To Afford Secondary Amines at Ambient Temperature

“…Intermolecular self-condensation of primary amines (RNH 2 ) is one of the most efficient methods for the synthesis of symmetric secondary amines (R 2 NH, Scheme a). − The beauty of this clean reaction scheme is illustrated by the highly atom-economical and selective production of the target secondary amine and the coproduction of ammonia as the only byproduct. The self-condensation process is free from the problem of organic waste formation involved in the conventional N,N-dialkylation of primary carboxamides or sulfonamides followed by cleavage of the amide moieties .…”

“…Next, we tested the cross-condensation of two different amines . Whereas reactions of 1a with n- butyl or n- octylamine gave complex mixtures, reasonable amounts of cross-condensation products were obtained in the reaction of methylamine with 1a ; N- methylbenzylamine formed in 43% yield together with N , N -dimethyl­benzylamine (4%, Scheme ).…”