[1] UNIV MIAMI, DEPT CHEM, CORAL GABLES, FL 33124 USA
[2] TWENTE UNIV TECHNOL, ORGAN CHEM LAB, ENSCHEDE, NETHERLANDS
[3] UNIV COLL OXFORD, OXFORD OX1 4BH, ENGLAND
[4] SWISS FED INST TECHNOL, ORGAN CHEM LAB, CH-8092 ZURICH, SWITZERLAND
[5] UNIV LIVERPOOL, DEPT CHEM, LIVERPOOL L69 3BX, ENGLAND
[6] CORNELL UNIV, MED CTR, NEW YORK HOSP, DEPT BIOCHEM, NEW YORK, NY 10021 USA