The chiral tridentate spiro P‐N‐S ligands (SpiroSAP) were developed, and their iridium complexes were prepared. Introduction of a 1,3‐dithiane moiety into the ligand resulted in a highly efficient chiraliridium catalyst for asymmetrichydrogenation of β‐alkyl‐β‐ketoesters, producing chiralβ‐alkyl‐β‐hydroxyesters with excellent enantioselectivities (95–99.9 % ee) and turnover numbers of up to 355 000
What a turnover! An efficient chiraliridiumcatalyst that bears a tridentate spiro aminophosphine ligand catalyzes the asymmetric hydrogenation of ketones with excellent enantioselectivities (up to 99.9 % ee) and extremely high turnover numbers (TONs; as high as 4 550 000).
practical method for efficient asymmetric hydrogenation of β-aryl alkylidene malonates. With a site-specifically tailored chiral spiro iridium catalyst, a series of β-aryl alkylidene malonate esters were hydrogenated to afford chiral malonate esters with good to excellent enantioselectivities (up to 99% ee) and high turnover numbers (up to 19000). The results showed that installing an ester group in α,β-unsaturated
A new type of tridentate chiral spiro aminophosphine−oxazoline ligands (SpiroOAP) have been synthesized through four steps. The SpiroOAP ligands are highly efficient for the asymmetric hydrogenation of α‐keto amides, providing a variety of synthetically useful α‐hydroxy amides with excellent enantioselectivity (up to 98% ee) and turnover numbers (up to 10,000).