Iridium-Catalyzed Asymmetric Hydrogenation of Unprotected β-Enamine Esters

Significance Expanding their work on the asymmetric hydrogenation methodology, this work demonstrated a highly efficient enantioselective hydrogenation of unprotected β-enamine esters catalyzed by an iridium ( S , S )-f-binaphane complex. The free β-enamine acids were obtained in excellent yields and enantioselectivities (for asymmetric hydrogenation of unprotected NH imines, see: G. Hou, F. Gosselin, W. Li, J. C. McWilliams, Y. Sun, M. Weisel, P. D. O’Shea, C.-y. Chen, I. W. Davies, X. Zhang J. Am. Chem. Soc. 2009 , 131 , 9882).