Development and Mechanistic Studies of Ti-Mediated C-N and N-N Coupling Reactions

Abstract

This thesis describes our recent efforts on C-N and N-N coupled nitrene transfer reactions via Ti imido complexes. These studies aim to explore the compatibility of Ti(IV/II) redox catalysis with various chemical transformations through mechanistic interrogation and reactivity of model compounds, for the development of new Ti-catalyzed nitrene transfer reactions. Chapter 1 explains the background and challenges in Ti-mediated C-N and N-N coupling reactions. Chapter 2 describes the application of boryl and stannyl alkynes in Ti-catalyzed [2+2+1] pyrrole synthesis and the subsequent Pd-catalyzed cross-coupling reactions for highly functionalized pyrroles. Chapter 3 covers the exploration of alternative nitrene sources in Ti-catalyzed hydroamination via a Ti(IV/II) redox process. Chapter 4 details the mechanistic investigation of the sequential one-electron oxidation processes in the oxidative pyrazole synthesis from diazatitanacyclohexadiene. In chapter 5, a preliminary study on N–N coupled indazole synthesis from diazatitanacyclohexadiene with an extended aromatic system is reported.