Abstract
Abstract This dissertation describes development of new synthetic organic transformations by using gold salts. The use of this soft alkynophilic metal enables mild, diastereoselective and efficient transformations of a variety of readily available substrates to wide range of synthetically useful highly functionalized products. For better understanding the thesis is divided into four chapters. The first chapter deals with the gold-catalyzed 1,2-oxoarylations of nitriles with pyridine-derived oxides. This is the first success in the gold-catalyzed oxoarylations of nitriles using gold carbenes as initiators leading to benzo[d]azepine frameworks. Such azacyclic core is one of the most commonly encountering skeletons in nature and the core scaffold has a wide spread application in structural, biological importance. These oxoarylations were also achieved satisfactorily in intermolecular three-component oxidations, including diverse alkenyldiazo esters, nitriles, and pyridine-based oxides. The second chapter deals with the gold-catalyzed regiocontrolled [2+2+2]-cycloadditions of ynamides with two discrete nitriles to construct 4-aminopyrimidine cores pharmaceutically important structural motifs. The utility of this new cycloaddition is manifested by the excellent regioselectivity with applicable ynamides and nitriles over a wide scope. The third chapter describes the retention of stereochemistry in gold-catalyzed formal [4+3]-cycloaddition of epoxides with arenyanamides. The utility of this new [4+3]-Cycloaddition reaction is manifested by a wide scope of arenynamides and epoxides. An SN2-type front-side attack of phenyl at the oxiranyl ring is expected to cause the retention of stereochemistry. The fourth chapter presents gold-catalyzed 1,2-difunctionalizations of aminoalkynes using Only N- and O-containing oxidants. In the presence of IPrAuNTf2, nitrosobenzenes implements a novel oxoimination of aminoalkynes to form 2-oxoiminylamides that are then subjected to NaBH4 reduction in situ to deliver 2-aminoalcohols.