Luche Reduction

The selective 1,2-reduction of enones with sodium borohydride is achieved in combination with CeCl₃.

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Mechanism of the Luche Reduction

CeCl₃ is a selective Lewis acid catalyst for the methanolysis of sodium borohydride. The resulting reagents, various sodium methoxyborohydrides, are harder reducing agents (according to HSAB principles) and therefore effect an 1,2-reduction with higher selectivity.

Furthermore, CeCl₃ activates methanol.

Recent Literature

Reduction of ketones to alcohols using a decaborane/pyrrolidine/cerium(III) chloride system in methanol
J. W. Bae, S. H. Lee, Y. J. Jung, C.-O. M. Yoon, C. M. Yoon, Tetrahedron Lett., 2001, 42, 2137-2139.

Asymmetric 1,2-Reduction of Enones with Potassium Borohydride Catalyzed by Chiral N,N'-Dioxide-Scandium(III) Complexes
P. He, X. Liu, H. Zheng, W. Li, L. Lin, X. Feng, Org. Lett., 2012, 14, 5134-5137.

Chemoselective Luche-Type Reduction of α,β-Unsaturated Ketones by Magnesium Catalysis
Y. K. Jang, M. Magre, M. Rueping, Org. Lett., 2019, 21, 8349-8352.

Applications of Lanthanide Trichloride Hydrates Prepared from Mischmetall in Luche-Type Reduction
M.-I. Lannou, F. Hélion, J.-L. Namy, Synlett, 2007, 2707-2710.

A Facile Approach to the Synthesis of Allylic Spiro Ethers and Lactones
M.-C. P. Yeh, Y.-C. Lee, T.-C. Young, Synthesis, 2006, 3621-3624.