Affiliation: | 1. Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (UK);2. Schering Plough Corporation, Newhouse, Lanarkshire, Scotland ML1 5SH (UK);3. Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK) http://msmith.chem.ox.ac.uk |