IMPROVED PROCESS FOR PREPARING ENANTIOMERICALLY HIGH- PURITY ( 5,5'-DICHLORO-6,6'-DIMETHOXYBIPHENYL-2,2'-DIYL)- BIS-(DIPHENYLPHOSPHINE OXIDE)

摘要

PROBLEM TO BE SOLVED: To provide an improved process for preparing the bis- diphenylphosphine oxide set forth in the title by starting from a phosphorus oxide of the type O=P(phenyl)2(Cl) and 5-bromo-2-chloroanisole. SOLUTION: This process for preparing the bis-diphenylphosphine oxide comprises reacting an aromatic bromine compound with diphenylphosphinic oxide, forming a diphenylphosphine oxide and carrying out isolation thereof by adding a saturated aliphatic hydrocarbon to a solution in an aromatic hydrocarbon in a first stage, metalating the diphenylposphine oxide in the 6-position, reacting the resultant metalated compound with iodine and thereby forming a 2-iodo-diphenylphosphine oxide in which the temperature used therein is >=-25 deg.C and carrying out the process such that a small amount of iodine is always present in excess in a second stage.