Novel C-C and C-heteroatom bond forming synthetic strategies for the construction of potential scaffolds by NHC-catalysis and difunctionalization of arynes

Abstract

Abstract: This thesis demonstrates our accomplishments in the field of N-heterocyclic carbene catalysis and aryne chemistry to construct novel organic scaffolds. Chapter 1 is divided into three sections. Section 1 provides information on NHC catalyzed reactions, in particular, the Stetter reaction with selected examples from literature, whereas section 2 and 3 deals with our work on N-heterocyclic carbene catalyzed Stetter reactions of aromatic aldehydes with maleimides and N-substituted itaconimides, respectively. The developed Stetter reactions worked well under operationally simple reaction conditions to afford value added succinimide derivatives. Chapter 2 describes our novel work on the application of NHC catalysis in the total synthesis of cruciferane natural product. Herein, we have developed an intramolecular 3+2 cyloaddtion of homoenolate with imine as a key step to construct the cruciferane scaffold. Chapter 3 is divided into three sections. Section 1 provides information on various modes of aryne reactions and illustrates the reactivity and selectivity of aryne insertion reaction in elementalelemental bond with the help of representative examples from the literature. Section 2 and 3 describes our studies on aryne insertion reaction in C-C and C-S bond, respectively. Section 2 shows the preparation of valuable ortho-methyl trifluoromethyl sulfide substituted benzophenones through aryne insertion in C-C bond. Due to fluorine’s intrinsic property of modifying the pharmacological properties of drug molecules, its installation in the organic molecule through aryne chemistry was our prime motive, which was achieved successfully. Section 3 involves utilization of sulfur ylide for difunctionalization of aryne via C-S bond insertion. This section demonstrates novel reactivity for sulfur ylides.