Highly enantioselective Michael addition of pyrazolin-5-ones catalyzed by chiral metal/N,N'-dioxide complexes: metal-directed switch in enantioselectivity
Angew Chem Int Ed Engl. 2011 May 16;50(21):4928-32.
doi: 10.1002/anie.201008256.
Epub 2011 Apr 14.