1. Instituto de Quimica-Fisica “Rocasolano”, CSIC, C/Serrano 119, 28006 Madrid, Spain
2. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, 117913 Moscow, Russian Federation
3. Department of Chemistry, University of Reading, Whiteknights, P. O. Box 224, Reading, RG6 6AD, U.K.