Stereoselective Carbon-Carbon Bond Construction Using Indium and Bismuth: New Methods in Green Chemistry
Abstract
Selective chemical reactions that can be accomplished with minimal waste using non-toxic catalysts and reagents will allow for new greener chemical processes for future environmentally sustainable technologies. This work will present an account on enantioselective nucleophilic addition to carbon-nitrogen and carbon-oxygen double bonds mediated by the environmentally benign indium and bismuth metals.
The dissertation entitled “ Stereoselective carbon-carbon bond construction using indium and bismuth: new methods in green chemistry” is divided into three chapters Chapter one outlines a few concepts in green chemistry and background information on the vital role of indium and bismuth in present day organic synthesis.
The development of a procedure for using allylic alcohol derivatives for ümpolung type allylation of chiral hydrazones is described in chapter two. This procedure affords homo allylic amines in good yields and excellent diastereoselectivity. An interesting study with respect to the mechanism of the reaction has been conducted. Switching gears towards the end of this chapter, ultrasound-promoted indium-mediated Reformatsky reaction of chiral hydrazones is described. This chapter describes a potential green chemical method for making β-amino acids.
In chapter three, indium mediated enantioselective allylation of α-ketoamides is described. The developed procedure is applied in the allylation of linear and cyclic α- ketoamides. Overall, an operationally simple and environmentally benign stratergy development has been explained. The later section of this chapter discusses the Reformatsky reaction in isatin series using the same protocol applied for imines.
To fully explore any organometallic reaction, it is important to understand the mechanism with which they operate at molecular level. Chapter three outlines some of our attempts to understand the enantioselective indium and bismuth mediated allylation and the nature of chiral- indium and bismuth Lewis acids. A postive non-linear effect has been observed and studied in bismuth-mediated allylation. Key findings obtained in each chapter and their implications to the future of our research is also discussed in each chapter. The chapters also details on what we understood about the potentials of organoindium and organobismuth chemistry towards developing new green chemical methods.