Asymmetric synthesis of chiral phosphines and arsines promoted by organometallic complexes

Abstract

This thesis describes the development of chiral cyclometalated-amine templates promoted asymmetric reactions such as the Diels-Alder, hydrophosphination and hydroarsination reactions for the synthesis of chiral phosphine and chiral arsine ligands. The [4+2] Diels-Alder reactions involving 3-diphenylphosphinofuran and three phosphine functionalized dienophiles viz. diphenylvinylphosphine, diphenyl[(E)-2-(ethoxycarbonyl)vinyl]phosphine and divinylphenylphosphine were carried out by employing platinum complexes containing the ortho metalated (R)-(1-(dimethylamino)ethyl)naphthalene (R)-86 as the chiral template to generate the endo-cycladducts. In chapter 1 the cycloaddition reaction between diphenylvinylphosphine and di-(3-furyl)phenylphosphine is also presented. The chiral naphthylamine auxiliary in the isolated chelating diphosphine endo-cycloadduct metal template complexes could be removed chemoselectively by treatment with concentrated sulfuric acid, during which the oxanorbornene skeleton of the diphosphine metal complexes is inert to the acid treatment. Further ligand liberation from the resultant dichloro complexes using aqueous cyanide gave the free bis(diphenylphosphino)-substituted cycloadduct ligands which are air stable. The asymmetric [4+2] Diels-Alder reaction involving 3-diphenylphosphinofuran as the dienophile and 3,4-dimethyl-1-phenylphosphole, DMPP, as the cyclic diene was carried out by utilizing the platinum(II) template complex (R)-86 as the chiral