Stereoselective Synthesis Of Chiral Secondary Phosphine Compounds And Chiral Chelated Tertiary Phosphine Ligands

Chiral organic phosphine ligands play an important role in asymmetric synthesis.They can be used as both ligands of metal catalysts and organic catalysts,and play an important role in asymmetric catalysis,organic synthesis,bioengineering and other aspects^[1].This thesis is mainly divided into three parts:the P-O bond fracture of the diisomerized alkoxy phosphine compound is converted to phosphorus anion,and then stereoselective alkylation is carried out;Stereoselective synthesis of chiral dialkylphosphoborane complex;chiral tertiary phosphoborane complex and bisphosphoborane complex were prepared and the intramolecyclization of bisphosphoborane complex.First of all,the heterogeneous compound 2a/2a’was used as raw material.The lithium naphthalene reagent was used to explore the rupture of the phospho-oxygen bond.Under the condition of toluene as the solvent at room temperature,lithium naphthalene reagent was added to form phosphorus anions 3a/3a’,which can reach the dselectivity of85:15 through the differential isomerization balance,and form the selectivity of chiral tertiary phosphoborane complex 5 by alkylation reaction.It can be further improved to96:4.When the method is extended to acyclic alkoxy phosphoborane complex 2b/2b’,the selectivity of the product is similar to that of 2a/2a’.Compound 5 was further alkylated to modify phenolic hydroxyl group.Complexes 9a,9b and 9c were prepared by oxyalkylation of R_P-5ab under basic conditions.Secondly,the racemic transformation of chiral dialkylphosphoborane complex is investigated.A single stereoselective dialkylphosphoborane complex was synthesized.The P-O bond of Binadiphenol oxyaryl menthol phosphoborane complex 15is broken by lithium naphthalene.In the end,a series of single stereoselective chiral tertiary phosphine complexes 6 and bisphosphine 16 were prepared by alkylation.The intramolecular cyclization of bisphosphine compound was achieved.