Transition Metal Catalyzed C-H Functionalization: Construction of C-C, C-O and C-X Bonds
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Cross-coupling reactions are widely used in both industry and academia for the installation of functional group and untied a new gate in organic synthesis. However, now-a-days CH functionalization strategies have received significant attention from the atom economy point of view. In this context two fundamental approaches viz. ligand directed CH functionalization and cross-dehydrogenative coupling (CDC) are the most preferred synthetic protocols. The thesis work based on the development of directing group assisted site selective C−H activation protocols to generate caraboncarabon (C−C) and carbonheteroatom (C−X) bonds. Two privileged motifs present in many naturally occurring molecules such as benzothiazoles and quinoxalines were used for ortho-selective aroylation, carboxylation and halogenations. For o-aroylation and o-carboxylation both 2,3 diarylquinoxalines and 2-arylbenzothiazoles provided mono-o-functionalized product whereas for o-halogenation of 2-arylbenzothiazoles afforded di halogenated product which is quite different from usual reports. The thesis work also consists of non activated keto amide sp3 C−H functionalization in the presence of Pd(II)/Cu(II) combination. Apart from these work, a ,-sp3 C−H functionalization strategy of tertiary amines was also developed for the cycloaddition reaction.
Supervisor: Bhisma K. Patel