Silica gel supported pyrrolidine-based chiral ionic liquid as recyclable organocatalyst for asymmetric Michael addition to nitrostyrenes

A novel silica gel supported pyrrolidine-based chiral ionic liquid 6a has been developed and found to be a highly effective catalyst for the Michael addition reaction of ketones with nitrostyrenes. The reactions generated the corresponding products in good yields (up to 94%), excellent enantioselectivities (up to >99% ee), and high diastereoselectivities (up to >99:1 dr). In addition, the catalyst 6a can be reused at least five times without a significant loss of catalytic activity and stereoselectivity.