Patent ID: 7067690

Claim:
A process for modifying the relative ratios of the components of a liquid starting mixture of diastereoisomers of formula (I) in which the diastereoisomers have at least two asymmetric carbon atoms, n is an integer from 0 to 2, R 1 , R 2 , R 3 and R 4 , same or different to each other, are H or C 1 –C 20 hydrocarbon groups, optionally containing heteroatoms, G is a —COOR′, —OR′, —C═OR′, —NR 2 ′, or —PR 2 ′ group, wherein R′ is H or C 1 –C 20 hydrocarbon groups, optionally containing heteroatoms, the process comprising the following steps: (i) contacting said liquid starting mixture with a Lewis acid compound, capable of co-ordinating at least one component of the starting mixture, which is used in an amount not enough to co-ordinate the total amount of the diastereoisomeric components of the liquid starting mixture; and (ii) subjecting the resulting mixture to conditions such that a reaction product, having a molar ratio between its diastereoisomeric components different from the corresponding molar ratio in the said liquid starting mixture, becomes separated from the said liquid mixture.