Recent advances on catalytic asymmetric hydrogenation of oximes and oxime ethers

The asymmetric hydrogenation of imines has been well-established; however, the asymmetric hydrogenation of oximes and oxime ethers with the retention of NO bonds remains a significant challenge in the realm of asymmetric hydrogenation, due to the low reactivity and the difficulty in control of stereoselectivity. Catalytic asymmetric hydrogenation of oximes or oxime ethers represents one of the most direct and efficient method for the construction of chiral hydroxylamines, which are key structural motifs in a wide range of bioactive compounds and pharmaceuticals. This review describes the recent progress in the development of catalytic asymmetric hydrogenation of oximes and oxime ethers. We hope that this review will inspire the development of new synthetic strategies for the asymmetric synthesis of chiral hydroxylamines.