The asymmetric copper-catalyzed generation and subsequent [2, 3]-sigmatropic rearrangement of sulfur ylides is strongly dependent on the structure of the starting allyl sulfide. A series of alkyl and aryl substituted allyl sulfides (2a-i) were reacted with ethyl diazoacetate in the presence of copper triflate (CuOTf) and a C 2-symmetric bis-oxazoline ligand (5a-c). The degree of asymmetric induction ranged from 2.8% for allyl methyl ...
