Completing the Cycle: Ring Opening and Ring Closing Reactions for Complex Heterocycle Synthesis

By Zoom: https://uqz.zoom.us/j/86873007565?pwd=bWlISVVLNXdPdE5rTTg0VVVaOVhWQT09

Our research program is centred around developing new synthetic methods for the preparation of complex
heterocyclic molecules, with a focus on transition metal-catalysed processes. Our group works closely with
computational chemistry collaborators in order to develop a detailed mechanistic understanding of the
reactions we develop. This presentation will provide an overview of the chemical reactions and mechanistic
investigations recently discovered in our laboratory.

This talk will cover our work on the deployment of highly strained vinylaziridines,
vinylcyclopropanes and cyclopropenes in Pd- and Au-catalyzed cycloaddition reactions to produce
biologically relevant heterocycles, including the pyrroloindolines, tetrahydro-B-carboines and the fused
heterocyclic motifs found in the core of the Curcusone I and J diterpenes. The synthesis and Pd- and Nicatalysed
reactivity of next generation molecular building blocks developed in our laboratory including, Allen-
Ox and Allenyl-B will also be discussed. Collaborative work with CSIRO on non-catalyzed intramolecular
azomethine ylide cycloaddition reactions to nitro-aromatics will also be discussed.

In the second part of the talk, the development of metal-catalysed tetrahydro-Diels–Alder (TDDA)
reaction of polyunsaturated enediyne systems and the computational investigation of the associated reaction
mechanisms will presented. The TDDA reaction is of particular note as it allows for the direct formation of a
benzenoid ring in a single step, via an intriguing high energy cyclic allene intermediate. The thermal mode of
this reaction has been investigated for many years, but its synthetic applications are severely limited by the
requirement of the process for very forcing reaction conditions and particular substitution patterns on the
starting materials. Our recent work on Rh- and Au-catalysed TDDA reactions has enabled this reaction to be
a practical process in organic synthesis.