| The first part of this dissertation describes copper hydride chemistry under environmentally attractive conditions by taking advantage of micellar catalysis. Reactions can be performed in water at room temperature. The combination of silane PMHS, nonracemic ligand, and amphiphile has led to a viable, "greener" method for this otherwise well-established transformation normally run in organic solvents at low temperature. In addition, the Cu-catalyzed conjugate addtion of carbon nucleophiles can be done in pure water, even though it as yet has not synthetically useful.;The second part focuses on facile C--H activation reactions of aryl ureas with arylboronic acids and arcrylates at room temperature catalyzed by a dicationic palladium complex. Some evidences as the mechanisms involved were also obtained. A cationic Pd(II) complex was found to smoothly react with aryl ureas to rapidly produce the corresponding cationic palladacycle at room temperature. The structure of the palladacycle was determined by X-ray analysis.;Finally, significant progress has been made towards the atropselective syntheses of axial chiral biaryl natural products in our group. During the course of these studies, an asymmetric total synthesis of (+)-korupensamine B has been completed in 7% overall yield, with a longest sequence of 18 steps from commercially available materials. This concise synthesis features a stereocontrolled biaryl coupling between the highly functionalized naphthyl and THIQ subsections. The construction of the naphthylisoquinoline framework may invoke pi-stacking interactions as a source of stereocontrol. Furthermore, in order to make the tether ligand reusable, an ester linker instead of ether linker was redesigned and synthesized for the synthesis of the AB ring system of vancomycin. Thirdly, combining these concepts with previous studies, we are aiming at enantioselective synthesis of (-)-marinopyrrole A, via a direct coupling of two fully elaborated pyrrole units. The synthetic pathway to fully elaborated pyrrole units has been developed. Further studies on vancomycin and marinopyrrole A are currently being investigated in our laboratories. |
