1. Département de Chimie Moléculaire (SERCO) UMR-5250, ICMG FR-2607, CNRS−Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 09, France, and Laboratory of Glycochemistry and Asymmetric Synthesis, Ecole Polytechnique Fédérale de Lausanne, Batochime, CH-1015 Lausanne, Switzerland