Sugar-Based Pyrrolidine as a Highly Enantioselective Organocatalyst for Asymmetric Michael Addition of Ketones to Nitrostyrenes

A modular sugar-based pyrrolidine (3) was prepared and was found to be a highly enantioselective organocatalyst for the asymmetric Michael addition of ketones to nitrostyrenes. In the presence of 10 mol% of 3, a pyrrolidine unit anchored to a natural D-glucose backbone through click chemistry, the Michael additions of ketones to nitrostyrenes proceeded smoothly to generate the corresponding adducts in good yields (up to 98%), high enantioselectivities (up to > 99% ee) and excellent diastereoselectivities (up to > 99:1 dr) under solvent-free reaction conditions.