1. AnorMED Inc., 200‐20353 64th Ave., Langley, BC, V2Y 1N5, Canada, Fax: +1‐604‐530‐0976
2. Present address: Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
3. Present address: Department of Chemistry, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada
4. Department of Biological and Chemical Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
5. Department of Chemistry, Syracuse University, Center for Science and Technology, Syracuse, NY 13244‐4100, USA