Doctor of Philosophy (Ph.D.)
Degree Granting Department
Xiaodong Michael Shi, Ph.D.
James Leahy, Ph.D.
Jianfeng Cai, Ph.D.
Lei Wang, Ph.D.
Alkyne Trifunctionalization, Azaborine, Benzotriazole, Hydroboration
This dissertation mainly contains three parts: 1) Divergent gold catalysis for alkyne trifunctionalization, encompassing three distinct modes to achieve the simultaneous formation of C-N, C-O, and C-C bonds in a single step 2) the study and development of a new method to synthesize azaborine derivatives; and 3) the construction of benzotriazole boranes (BTAB) as stable four-coordinate N-B heterocycles through gold-catalyzed alkyne hydroboration.
In the first part, alkyne trifunctionalization via divergent gold catalysis will be introduced. This novel approach involves a sequence of reactions that combine gold π-activation, vinyl gold nucleophilic addition, and gold (III) reductive elimination. By utilizing this methodology, we demonstrate a new strategy for employing vinyl-AuIII as highly effective nucleophiles in bond construction. In this process, aryl diazonium salts are identified as efficient electrophiles and oxidants. Notably, this work represents the pioneering example of a transformation that successfully integrates all three gold reaction modes within a single step.
In the second part, a new method for the synthesis of substituted cyclic amine-borane compounds via gold-catalyzed hydroboration will be discussed. One of the limitations of our previous work in synthesizing azaborine is the oxidation step. We’ve developed a method to introduce different functional groups in the C4 position of the cyclic amine-borane. This foundational research paves the way for further investigations and provides us with the opportunity to achieve the azaborine form of the cyclic N-B complex using gold-catalyzed alkyne hydroboration.
In the third part, gold-catalyzed alkyne hydroboration for synthesizing stable four-coordinate N-B heterocycles will be presented. Develop a new method to synthesize polymeric (BH2CN)n by combining benzotriazole borane (BTAB) to stabilize borane, allowing for synthesizing a new class of N-B heterocycles BTABs. These BTABs exhibit a solid and tunable Fl emission up to 561 nm, making them promise new molecular probes for chemical research.
In summary, we have explored two types of alkyne functionalization via gold catalysis. The first instance of alkyne trifunctionalization employing three distinct gold reaction modes, has been successfully accomplished. We have successfully achieved gold-catalyzed alkyne hydroboration to synthesize stable four-coordinate cyclic amine-borane compounds. Furthermore, we have conducted additional studies on the functionalization of these compounds.
Scholar Commons Citation
Tang, Qi, "Investigation of Challenging Transformations in Gold Catalysis" (2023). USF Tampa Graduate Theses and Dissertations.