Research On Asymmetric Reduction Of 2-chloro-3-oxo Esters Via Transfer Hydrogenation And Design And Synthesis Of A New Kind Of Chiral Br(?)nsted Acid

A study on the reduction of 2-chloro-3-oxo esters via asymmetric transfer hydrogenation1. A series of 2-chloro-3-oxo esters have been synthesized in good yield. All products have been well confirmed by 1H NMR. It was found that this kind of compounds exist as an equilibrium mixture of keto- and enol-forms.2. Asymmetric reduction of of the above 2-chloro-3-oxo esters was achieved by their asymmetric transfer hydrogenation using HCOOH : Et3N = 5 : 2 as the hydrogen source and (S,S)-TsDPEN-Ru(II) as the catalyst, providing the corresponding chiral 2-chloro-3-hydroxy esters with good enantioselectivities up to 98% ee and diastereoselectivity up to 7.1 : 1 dr.The design and synthesis of a new kind of chiral Br(?)nsted acid and a preliminary study on its propertiesA new kind of chiral Br(?)nsted acid was designed and synthesized, and its structure was characterized by 1H NMR, 31P NMR and HRMS. A preliminary study has been done on its properties in some reactions such as asymmetric transfer hydrogenation.