Kumada and liebeskind-srogl coupling of aryl thiosulfonates as electrophilic coupling partners in the synthesis of biaryls.

Abstract

The need and desire for versatility and diversity in cross-coupling reactions was the drive for the studies conducted in this thesis. Traditionally, transition-metal catalyzed crosscoupling reactions have heavily relied on organohalides and pseudo-halides as electrophilic-coupling partners. As a result, alternative compounds such as organosulfur compounds, which are potential electrophilic-coupling partners, have often been overlooked and subsequently understudied. Hence, this study was aimed at exploring the reactivity of S-phenylarylthiosulfonates as electrophilic-coupling partners in the transition metal-catalyzed cross-coupling such as Liebeskind-Srogl and Kumada-Corriu crosscoupling reactions towards the synthesis of biaryls. In this study, disulfides were synthesized from the economical, time-efficient and catalystfree oxidation of thiols in good to excellent yields (70-83%). The disulfides were in-turn reacted with sodium arylthiosulfonates to produce the desired symmetrical and unsymmetrical S-arylthiosulfonates in 69-73% yields. With different S-arylthiosulfonates in hand, we investigated their reactivity as electrophilic coupling partners in transition metal catalyzed C-C bond forming cross-coupling reactions, namely: Kumada-Corriu and Liebeskind-Srogl in an attempt to expand the scope of electrophilic coupling partners in organic synthesis portal.