Expeditious Thermal Photo Induced Functionalization Annulation En route to N Heterocycles

Abstract

The content of the thesis has been divided into four chapters. The thesis streamlines the synthesis of aromatic and non-aromatic N-heterocycles. It contributes towards the facile formation of Cand#8722;C, Cand#8722;N, Cand#8722;O and Cand#8722;S bonds using o-alkynylanilines, maleimides, 2-aryl quinoxalines, (benz)imidazoles, boronic acids and disulfides. Chapter I introduces transition metal induced (thermal) and photochemical construction of Cand#8722;C and Cand#8722;Heteroatom bonds. The mechanism involved in both transition metal induced (thermal) and photochemical approach are discussed. Both the processes are explained in details with the help of suitable examples. Chapter II describes a Cu(I) mediated cascade cyclization/annulation of unprotected o-alkynylanilines with maleimides in one-pot. The protocol offers sequential formation of one Cand#8722;N and two Cand#8722;C bonds to deliver fused benzo[a]carbazoles having free NH skeletons. The annulated products have been exploited towards various applications. Chapter III describes a Cu(OTf)2 mediated regioselective de-aromatized aryl-hydroxylation across C(sp2)=N bond of 2-aryl quinoxalines and bis-N-arylation of (benz)imidazoles using aryl boronic acids. For dearomative aryl-hydroxylation, the C-center should be electrophilic (ca. 0.08), N-center nucleophilic (ca. and#8722;0.50), and the C(sp2)=N bond should be polarized (and#916;e = 0.609).