Title: Substituted Shape-Shifters and 8π/6π Synthesis
Speaker: Dr Thomas Fallon, School of Environmental and Life Sciences, The University of Newcastle
Abstract: Bullvalene is the archetypal shape-shifting molecule. Through endless rearrangements, the structure has no permanent carbon-carbon bonds, and substitueheronnts dynamically alter their arrangements. While discovered the 1960s, the chemistry of this enigmatic scaffold was largely forgotten. This seminar presents our general toolbox for the easy synthesis of bullvalenes, an exploration of their dynamic nature. We explore a range of avenues toward applications in adaptive binding, supramolecular self-assembly, and medicinal chemistry.
This seminar will also discuss the endidiandric acids - the most famous of the bicyclo[4.2.0]octadiene derived natural products. The spectacular 8π/6π/Intramolecular Diels-Alder pericyclic reaction cascade at the heart of their biosynthesis has inspired students and practitioners of biomimetic synthesis for over four decades.
Most previous synthetic approaches target a linear tetraene intermediate in order to trigger the 8π/6π/DA cascade. However, this requires the lengthy stepwise stereoselective synthesis of the linear tetraene. We reasoned that an overall strategic anti-vicinal difunctionalisation of cyclooctatetraene would intercept the 8π/6π cascade half-way, and provide rapid entry to the bicyclo[4.2.0]octadiene. This Poster presents three generations of this strategy. The first employs an epoxidation of cyclooctatetraene, followed by organocuprate addition, vinyl transfer, and Claisen rearrangement to a key bicyclo[4.2.0]octadiene intermediate. The second involves the cyclopropanation of cyclooctatetraene followed by direct organocuprate addition/ring opening to give an advanced bicyclo[4.2.0]octadiene in just two steps. The third, and unpublished approach explores the use of 1,3,5-cyclooctatrieneone. Simple alkylation followed 6π/IMDA gives an advanced tetracyclic intermediate as a staging post for practical and versatile derivatisation to a range of targets.
About School research seminars
Seminars cover all aspects of chemistry and molecular biosciences and are delivered by visiting national and international academics. PhD completion seminars are also incorporated into the program.
Seminars are usually held in person and via zoom. All are welcome to attend.
Contacts
- Chemistry: Dr Rowan Young, Dr David Cantillo
- Molecular Biosciences: Dr Mathew Jones