A 4-Hydroxy Pyrrolidine Catalyzed Mannich Reaction of Aldehydes: Control of Anti-Selectivity by Hydrogen Bonding Assisted by Bronsted Acids E. G. Bengoa, M. Maestro, A. Mielgo, I. Otazo, C. Palomo, I. Velilla, Chem. Eur. J. 2010, 16, 5333-5342
