Organocatalytic asymmetric conjugate addition of aldehydes to nitroolefins: identification of catalytic intermediates and the stereoselectivity-determining step by ESI-MS
Angew Chem Int Ed Engl. 2013 Nov 25;52(48):12619-23.
doi: 10.1002/anie.201305338.
Epub 2013 Oct 2.