Michael Addition Catalyzed by Chiral Bifunctional Thioureas Based on Saccharides

Significance

Ma and co-workers synthesized ­bifunctional thioureas derived from commercially available saccharides and chiral diamines. These simple catalysts proved to be efficient in the Michael-type addition of ketones to α,β-,γ,δ-nitrodienes giving perfect regioselectivity for the 1,4-addition. The corresponding products were obtained in high yields and enantioselectivities and could be easily converted into the trans- and cis-(3R)-5-substituted 3-pyrrolidine carboxylic acids.