| The copper(I) carboxylate-mediated, palladium-catalyzed coupling of various thioorganics has been proved efficient with both boronic acids and organo-tri-n-butylstannanes. However, certain limitations are to be studied. As a case in point, the coupling of thiol esters have been successfully developed for various substituents on the thiol ester (aromatic, heteroaromatic, aliphatic), and with aromatic, heteroaromatic, and alkenylboronic acids, but not with aliphatic boronic acids. An exploration of extending the thiol ester cross-coupling protocol to include aliphatic organoboron reagents was therefore performed. Through the use of B-alkyl-9-BBN derivatives, cross-coupling of thiol esters was broadened to include aliphatic boron reagents. In the presence of a base, aryl-alkyl and alkyl-alkyl ketones with a variety of functional groups were synthesized in moderate to excellent yields. Moreover, an investigation of the cross-coupling of alkenyl sulfides with organoboron reagents was also carried out to fulfill the protocol. It was found that olefins with trans configuration could be obtained in good yields using a rhodium(I) catalyst in the presence of a copper(I) carboxylate mediator.; Application of the copper(I) carboxylate-mediated, palladium-catalyzed cross-couplings of thioorganics to solid phase synthesis was also explored. Thiol esters and heteroaromatic thioethers were attached to different solid supports via different linkers. By using water-soluble Pd catalysts, the coupling of modified polymers with boronic acids successfully gave the desired coupling products in the solution phase.; Transition metal-catalyzed reactions of various heteroatom-heteroatom reactants with mild reaction partners would provide new and mild approaches for carbon-heteroatom bond formation. Carbon-nitrogen bond formation from a series of N = O and N-O compounds has been investigated. A copper(I)-mediated reductive amination of boronic acids with nitroso aromatics was observed, giving unsymmetrical diarylamines in good yields. The reaction was accomplished by using a stoichiometric quantity of copper(I) or catalytic copper(I) carboxylate and an external reducing agent. Hydroxylamine derivatives, with lower oxidation state than nitroso compounds, were then employed in the copper-mediated amination of boronic acids. Amides were obtained from O-substituted hydroxamic acids in formation of carbon-nitrogen bond. O-Substituted oximes also participated in the copper(I)-catalyzed amination of boronic acids or organotin compounds, giving ketimines in good yields. |
