Abstract
In recent year transition-metal-catalyzed C‒H activation reaction got considerable attention because of catalytic reaction does not require pre-functionalization also desired product is highly regioselective and utility of reaction can be applicable to synthesis biologically important compounds in one pot operation with high atom-efficacy. In this thesis, aerobic rhodium–catalyzed inter and intra molecular C‒H Bond functionalization reactions are described. For better understanding, I divided this thesis into three chapters. The first chapter describe about rhodium-catalyzed ortho olefination via intramolecular aza-michael addition in water and oxygen as a sole oxidant. In chapter second rhodium catalyzed intramolecular C‒H activation/annulation of aldehydes with alkyne-amines demonstrated in presence of oxygen as an oxidant. The third chapter describe about synthesis of isoquinolones from N-alkyl benzamides and alkynes using Rh(III) catalyst and inexpensive oxygen as the sole oxidant in aqueous medium. Chapter 1 describes a new method for the synthesis of Isoindolium Salts from from 2-arylpyridines and alkenes in aqueous medium under oxygen via Rh(III) catalysis. A reaction mechanism involving an ortho CH olefination of 2-arylpyridine by alkene, intramolecular aza-michael addition, deprotonation at the -carbon of the alkene fragment followed by another michael addition to give the final product is proposed. Chapter 2 deals with the synthesis of indolizidinium, quinolizinium and pyrido[1,2-a]azepinium salts synthesized from benzaldehydes (or ,-unsaturated aldehydes) and alkyne-amines catalyzed by rhodium complex via C–H activation is demonstrated. The present method is successfully applied to the synthesis of natural product, ficuseptine. Chapter 3 illustrates a new approach for highly regioselective synthesis of isoquinolones from N-alkyl benzamides and alkynes using Rh(III) catalyst and inexpensive oxygen as the sole oxidant in aqueous medium, in addition the methodology can be applied to the preparation of biologically active compounds having the isoquinolone core.