The Stereoselective Synthesis Of Chiral Tertiary Phosphines

In the asymmetric catalytic reaction,chiral tertiary phosphines can be used as organocatalysts and as ligands of metail catalysts.Chiral tertiary phosphines are important class of organic ligands,with broad applicability,high catalytic efficiency and specific chirality induction.The paper focuses on three parts: The synthesis of chiral hydrocarbyl menthyl phosphine oxide compounds;The stereoselectivity synthesis of tertiary phosphines boranes;The mechanism of nucleophilic substitution reaction based on optically pure chlorophosphine hydrochloride.First of all,in order to expand the range of functional groups of synthetic chiral secondary phosphine compounds,we used phosphorus trichloride as a starting raw material,through the reaction with binaphthyl diol,and then reaction with Grignard reagents.Using the axial chirality of(R)or(S)-(-)-1,1’-Bi-2-naphthol,when two hydrocarbon groups are introduced,respectivily,a chiral center is induced on the phosphorus atom to form a dihydrocarbylphosphine oxide in the R or S-configuration.By selecting(R)-or(S)-binadiol and the order of introducing two hydrocarbon groups,secondary phosphine oxide compounds with various structures and controlled chirality of the phosphorus atom can be synthesized with good yield and stereoselectivity.Secondly,a diastereomeric mixture of secondary phosphine oxide is treated with oxalyl chloride,and then reacted with aliphatic or aromatic Grignard reagents affords P-inverted or retained tertiary phosphines,respectively,in high to 99% yield and 99:1 dr.Finally,we conducted a series of experimental investigations on the synthesis,transformation,and structure of chlorophosphine and hydrochloride salt of chlorophosphine,and found that secondary phosphine oxide reacted with oxalyl chloride converted to chiral hydrochloride salt of chlorophosphine.The mechanism and stereochemistry of the substitution of P(III)-Cl species was first completed by us.