Abstract
This dissertation describes Gold & Silver-Catalyzed New Synthetic Methods to Access Highly Functionalized Carbocyclic and Heterocyclic Organic Molecules. It includes gold and silver metal which promotes efficient transformations of a variety of readily available substrates to wide range of synthetically useful carbocyclic and heterocyclic products. For better understanding, this thesis has been divided into four chapters The first chapter describes the Gold-Catalysed 1,2-iminonitronation of propiolate derivatives with nitrosoarenes to give α-imidoyl nitrones; This new reactions are applicable to diverse propiolate derivatives and nitrosoarenes to implement 1,2-oxidative functionalization of alkynes which finds various application in Agrochemicals. The second chapter deals with the Gold-Catalysed imination/Mannich reaction cascades on readily available 3-en-1-ynamides enable the diastereoselective synthesis of 1,5-iminoamino compounds in one-pot operation. The reactions work well with diversified 3-en-1-ynamides, aldehydes and anilines with good to excellent diastereoselectivities. Our control experiments indicate gold-catalyzed aminations of 3-en-1-ynamides to yield -imino allylgold intermediates that react subsequently with iminiums to implement the Mannich reactions stereoselectively. The reactions proceed with anti-selectvity for those 3-en-1-ynamides bearing acyclic alkenes whereas syn-selectivity is for their cycloalkene-based analogues. An open-transition state can satisfactorily rationalize these observed stereoselectivities based on an antiperiplanar conformation. The third chapter describes Gold-catalyzed [3+2]-annulations of α-aryl diazonitriles with ynamides and allenamides yield 1-amino-1H-indenes in two distinct pathways; the success of these annulations relies on the high electrophilicity of α-cyano arylgold carbenes to activate an ionic pathway. Indene molecule is highly desirable moiety in natural product and the resulting 1-amino-1H-Indenes can be used for the synthesis of bioactive molecules. The fourth chapter show development of novel Gold-Catalyzed intermolecular carbenoid functionalization of indoles with α-aryl diazo nitrile: Synthesis of bis(indolyl)-2-phenylacetonitrile via Double nucleophilic Addition Reaction. Reactions shows variety of scopes and yield a BIMs derivatives which is the core structures in many indole alkaloids such as Arsindoline A and B, Arundine, Viberindole A and Streptindole, these are very useful molecule in the treatment of many deseases.