improved process for the manufacture of enantiomerenreinen (5,5 '- the other ingredients are - 6,6' - dimethoxybiphenyl - 2,2 '- diyl) - bis (diphenylphosphinoxiden)

摘要

Four stage production of enantiomer-pure bis-diphenylphosphine oxides starting from an aromatic bromo-compound and a diphenylphosphine acid chloride is effected under specified conditions. Production of enantiomer-pure bis-diphenylphosphine oxides of formula (I) comprises: (i) reacting a bromo-compound of formula (IIa), after selective mono-metallization, with a diphenylphosphine acid chloride of formula (II) to give a diphenylphosphine oxide of formula (III); (ii) metallizing (III) in the 6-position and reacting with I2 to give a 2-iodo- diphenylphosphine oxide of formula (IV); (iii) converting (IV) with Cu to a racemic bis-diphenylphosphine oxide of formula (I); and (iv) crystallizing the racemic (I) with enantiomer-pure mono- or di-carboxylic acids to separate it into its enantiomers, the process being such that: (a) the solvent in step (i) is a mixture of THF and an aromatic hydrocarbon, the acid chloride (II) being added without solvent and the oxide product (III) being isolated from its solution in the aromatic hydrocarbon by addition of a saturated aliphatic hydrocarbon; (b) step (ii) is at not less than -25 degrees C and the metallized (II I) and I2 are introduced simultaneously such that there is always a small amount of I2 in excess, the iodinated intermediate (IV) being separated off dissolved in an aromatic hydrocarbon; (c) dendritic Cu and an aromatic hydrocarbon solvent are added in step (iii) and the racemic (I) is crystallized from solution in an aromatic hydrocarbon; and (d) an enantiomer-pure mono- or di-carboxylic acid is added and the first enantiomer is recovered by crystallization from solution in an aromatic hydrocarbon, while the second is recovered by hydrolysis followed by crystallization from solution in an aromatic hydrocarbon. R1 = phenyl, naphthyl, heteroaryl (with 4 or 5C and 1 or 2 N, O or S heteroatoms) or cyclohexyl, these optionally being substituted by R, OR, NO2, NH2, NHR or NR2; R = 1-6C alkyl; R2 = 1-4C alkoxy; R3 = H, F, Cl or Br; and R4 and R5 = H, F, Cl, Br or 1-6C alkyl or alkoxy.