| 摘要 |
PURPOSE: Provided is a process for the racemization of atropisomeric bis(phosphine oxide) compounds having (S) or (R) or non-racemic form for the preparation of optical active bisphosphine ligands which form optical active complexes with transition metals. CONSTITUTION: The racemization of the atropisomeric bis(phosphine oxide) compounds of the formula(1) is a thermal reaction and is performed in the presence or no presence of a pressure of 1x10¬5 - 3.5x10¬7Pa in a high boiling solvent at 260-400deg.C, wherein the thermal reaction is performed by heating or irradiating microwave. In the formula, R1 is C1-C8 alkoxy, R2 is hydrogen, C1-C8 alkyl, or C1-C8 alkoxy, R3 is hydrogen, C1-C8 alkyl, or C1-C8 alkoxy, and R4 is phenyl or substituted phenyl.
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