Asymmetric Reduction of Ketones

The enantioselective reduction of ketones to alcohols gives access to a pool of chiral building blocks that can be used for the synthesis of natural products. Adolfsson and co-workers reported a novel class of ligands, based on a pseudo-dipeptide,¹ for the mild and efficient reduction of ketones using 2-propanol as a hydrogen source. The ligand is used with [{RuCl₂(p-cymene)}₂] in presence of NaOH for the asymmetric reduction of a variety of acetophenone derivatives. Excellent yields and ee’s were reported (Scheme 1).

Scheme 1.

References

1. Bøgevig A, Pastor IM, Adolfsson H. 2004. Highly Enantioselective Ruthenium-Catalyzed Reduction of Ketones Employing Readily Available Peptide Ligands. Chem. Eur. J.. 10(1):294-302. https://doi.org/10.1002/chem.200305553