Professor Andrew Parsons

01904 322608
Email: andy.parsons@york.ac.uk

Radical approaches to the synthesis of biologically important heterocyclic compounds

The efficient preparation of medicinally and industrially important compounds using technically clean methods is an important challenge for modern synthetic chemists. Our interests focus on the synthesis of organic compounds using new radical reactions. Radical reactions offer some important advantages over more traditional synthetic methods and we are currently using new radical reactions in the enantioselective synthesis of medicinally important heterocycles. Target compounds of interest include the cannabinonid Δ9-THC and the anti-malarial agent quinine. We have a wide-ranging interest in radical reactions, so, apart from their use in the synthesis of small molecules, we are interested in polymerisation processes and natural oxidation reactions.

 structures of Δ9-THC and the anti-malarial agent quinine 
 

An important goal for synthetic chemists is the development of clean methods of radical generation, which have potential application in the chemical industry. To meet this challenge, we are investigating radical reactions of new manganese carbonyls and phosphorus hydrides under different conditions (e.g. using ionic liquids as solvents and/or microwaves in place of conventional heating). Our studies have shown that phosphorus hydrides (including chiral, polymer-supported and fluorous hydrides) undergo radical reactions to efficiently form organophosphorus adducts and this has led us to introduce the concept of radion reactions. Radion reactions involve sequential radical and ionic reaction steps in a one-pot transformation as shown below. The synthesis of target molecules without isolation of intermediates (saving time and resources) is an extremely powerful synthetic method that we are using in total synthesis.

reaction scheme 

Phosphorus hydrides supported on polymer beads