| Summary: | Conjugated olefins are readily available and inexpensive starting materials and their functionalization offers a rapid access to many important building blocks for organic synthesis. The functionalization of these olefins by asymmetric catalytic methods for the formation of C-C and C-X bonds is an active area of research. Major advances in this field are not only triggered by the development of new catalysts but also by engineering of new acceptor olefins. In our lab we have successfully developed acceptor olefins appended to alkoxyimidazoles as a novel template. Using these templated acceptors, we demonstrated methodologies to construct all carbon-quaternary centers, one of the demanding tasks in synthetic methodology development. We have also made significant efforts towards understanding the solution structures of the intermediates involved in the catalytic asymmetric reactions developed in our lab. In chapter 1, the importance of templated acceptors in the field of chemical synthesis with special emphasis on acylimidazoles is reviewed. The versatility of the N-alkylimidazole templates is showcased by their utility in several organic transformations. In chapter 2, modes of activation of acceptor olefins by catalysts, need for templated acceptors and challenges associated with designing an asymmetric catalytic process is described. Our approach in designing novel acceptors based on imidazoles is also described. In chapter 3 the synthetic utility of these novel N-alkoxyimidazole based acceptors is shown by enantioselective construction all carbon quaternary centers by Lewis-acid catalysis. We also compare the effectiveness of other templates such as oxazolidinone and N-methylimidazoles in the Lewis-acidic catalyzed Friedel-Crafts alkylation reaction. The effect of various parameters such as Lewis acid, chiral ligands, temperature, additives and solvents on the conjugate addition of Friedel-Crafts nucleophiles are presented in this chapter. In chapter 4, our research efforts toward understanding solution structures of intermediates involved in catalytic asymmetric reactions are presented. A combination of Diffusion Ordered Spectroscopy (DOSY), heteronuclear NMR spectroscopy, mass spectrometry and X-ray crystallography has been used to study the solution structure of intermediates involved in asymmetric catalytic reactions. In chapter 5, a future outlook on templated chemistry developed in our laboratory is presented. Some preliminary results pertinent to future projects are presented. === ND-EPSCoR: DDA (Grant FAR0021979)
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