Asymmetric Michael addition of aldehydes to nitroolefins catalyzed by a pyrrolidine-pyrazole

An effective protocol for the stereoselective Michael addition of aldehydes to nitroolefins using pyrrolidine-pyrazole as an organocatalyst is described. The catalytic cycle was found to be productive in terms of yield and selectivity, when performed under solvent-free reaction conditions and employing 15 mol % of catalyst and 10 mol % of benzoic acid at room temperature.