Chiral 1,5-, 1,6-, and 1,7-dienes generated in 3-4 steps from chiral auxiliary p-menthane-3-carboxaldehyde undergo RCM with notable discrepancies in reactivity depending on the nature and number of substituents flanking the central double bond. The chiral auxiliary is thus cleaved releasing a carbo- or heterocycle in the process. Special features concerning the RCM on these especially crowded systems are discussed. (c) 2006 Elsevier B.V. All rights reserved.
Efficient preparation of chiral non-racemic sulfur compounds
作者:Joannie Minville、Mélina Girardin、Claude Spino
DOI:10.1139/v07-091
日期:2007.9.1
p-Menthane-3-carboxaldehyde serves as an efficient chiralauxiliary in the preparation of chiralnon-racemic S-alkylthiocarbamates or S-dithiocarbonates via the 3,3-sigmatropic rearrangement of the corresponding alkylthionocarbamates or xanthates. The transfer of chirality during rearrangement is complete, and the final products possess a chiral tertiary or quaternary carbon bearing sulfur. The rearranged