The Design And Synthesis Of Chiral Phosphines And The Study On Enantioselective Intramolecular Rauhut-Currier Reactions

Asymmetric catalysis has became a hot research field in organic chemistry and was widely concerned by chemists for several decades. Among the research of asymmetric catalysis, the design and synthesis of chiral phosphines as organic catalysts and ligands are an important aspect and the key to promote the continuous development of the field.We used readily available aldehyde and 2-methylpropane-2-sulfinamide as the starting materials, which could get the corresponding imine in excellent yield in the presence of condensing agent. By using the imine as the substrate, a series of two types of chiral β-methylpropane-2-sulfinamide phosphine catalysts with different function groups were obtained through the addition reaction with diphenyl methyl phosphonic lithium. When applying chiral β-methylpropane-2-sulfinamide phosphine catalysts to the enantioselective intramolecular Rauhut-Currier reaction, we could get five membered cyclic lactones with up to 99% enantioselectivity under mild conditions. When using two different substituted racemic precursors, kinetic resolution and parallel kinetic resolution were observed with excellent yield and enantioselectivity. It was noteworthy that this is the first example of parallel kinetic resolution in enantioselective intramolecular Rauhut-Currier reactions.A series of chiral phosphoramide ligands with various groups were produced simply and efficiently through one-pot process with Grignard reagent or organo lithium reagent and diphenylchlorophosphine. The chiral phosphoramide ligands proved to be highly efficient in terms of yield in rhodium-catalyzed [2+2+2] cycloaddition reaction, however, the enantioselectivity was not satisfactory.