Research Fellows Directory
Professor Varinder Aggarwal
University of Bristol
In the same way that our hands and feet mirror each other, many molecules appear in two forms that mirror each other. Such molecules, called chiral molecules or enantiomers, come in pairs and, like our hands and feet, have both shape and function.
In order to sustain and maintain life Nature has evolved a highly complex system that allows a myriad of selective processes and reactions to occur without interference from each other. Many of these selective processes are triggered as a result of highly specific interactions between chiral receptors within cells (e.g. proteins) and molecules that have a particular shape and functionality. A key feature of the molecule’s shape is its chirality. When a molecule with the correct shape and chirality fits into its host receptor the interaction is akin to a hand fitting inside a glove and an appropriate response is generated. Pharmaceutical products therefore have to be tested and produced in one of the two mirror image forms.
During the past few decades there has been intensive research into developing methods for producing – synthesising – one of the two chiral forms specifically which was recognised by the award of the 2001 Nobel prize in Chemistry to the pioneers in this field.
In a synthesis starting molecules are used to build new molecules by means of various chemical reactions. Organic synthesis generally involves the reaction between two molecules – a nucleophile (-) and an electrophile (+). These are attracted to each other – rather like opposite poles of a magnet – and a chemical bond is created between them. We are working with a special class of reagents with a unique +/- reactivity since this allows multiple bonds to be created simultaneously. Furthermore, we are developing this chemistry so that when bonds are created, only one mirror image form is produced. In this way, chemists can use the new processes we have developed to make molecules more efficiently and with the appropriate chirality.