Date of Graduation
Eberly College of Arts and Sciences
Xiaodong Michael Shi
Jeffrey L Petersen
1,2,3-Triazoles as versatile directing group for selective sp 2 and sp3 C--H activation: cyclization vs substitution .;A selective cyclization and substitution was achieved with designated 1,2,3-triazole acid auxiliary groups as directing groups under Pd catalyzed C--H activation conditions. Both sp2 and sp3 C--H bonds were effectively activated, giving the desired products in good yields. This result revealed the first successful example of exclusive substitution using 1,2,3-triazole ligands, while other triazole-containing directing groups dominantly gave cyclization under identical conditions.;Palladium-Catalyzed Aerobic Oxidative C--H Olefination with Removable 1,2,3-Triazole Directing Group.;Ortho-olefination of arenes was achieved with removable 1,2,3-triazole auxiliary through Pd-catalyzed C--H activation. Excellent yields were received even when molecular O2 (1 atm) was used as the terminal oxidant. Other heterocyclic directing groups, such as pyridine and quinoline, gave poor reactivity under this aerobic oxidative condition, which highlighted the unique reactivity of triazole in promoting directed C--H activation.;Nickel-catalyzed directed sulfenylation of sp2 and sp3 C--H bonds.;Directed sulfenylation of both sp2 and sp3 C--H bonds was achieved via nickel catalyzed C--S bond formation, giving the desired product in good to excellent yield (up to 90%). Other metal cations including Cu, Fe, Pd, Rh, Ru and Co, gave almost no reaction under identical conditions, which highlighted the unique reactivity of this Ni system.
Ye, Xiaohan, "1, 2, 3-triazole as the Directing Group for Metal-Catalyzed C-H Activation" (2015). Graduate Theses, Dissertations, and Problem Reports. 7003.