Progress towards the total synthesis of Herquline A and B

• Main Author: Yang, He
• Published: University of Birmingham 2015
• Subjects: 540; QD Chemistry
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678876

Herquline A and B were isolated from the fungal strain \(Penicillium\) \(herquei\) Fg-372 and have been shown to exhibit potent platelet aggregation inhibitory activities. The unusual and strained structure of herquline A makes it a highly attractive and challenging synthetic target. Herquline B is conceived to be an analogue of herquline A, even though its absolute structure has not been elucidated. A biomimetic approach was initially investigated in Chapter 2, featuring an intramolecular direct oxidative phenol coupling strategy. While extensive experimentation failed to afford the desired coupling products, an advanced piperazine intermediate possessing a similar ring system to that in herquline A was accessed. Chapter 3 describes the transition metal-mediated intramolecular aryl coupling strategy. Small amounts of biaryl coupling products were fashioned. The conformational analysis of diketopiperazines and piperazines is also introduced. Chapter 4 describes the efforts in the synthesis of analogues of herquline B. The intramolecular coupling at the piperazine stage was found to be challenging and only trace amounts of the desired products were obtained.