Chiral scaffolds and their preparation

A salt according to any preceding claim, which is diastereoisomerically enriched.

A process for enhancing the diastereoisomeric purity of a salt of any preceding claim, which comprises crystallisation or recrystallisation.

Use of a salt according to any preceding claim, as an intermediate for a chiral molecular scaffold of formula (i)

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• or an alkyl ester thereof, or the opposite enantiomer thereof.

A process for the preparation of an enantiomerically enriched trans-1,4-disubstituted pipecolate derivative of formula (2), substantially free of the corresponding cis-isomer, which comprises selective hydrolysis of a mixture of diastereoisomeric esters (3a) and (3b)

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• wherein R1 is H, alkyl, alkoxy or aryl, R2 is H or alkyl, and R3 is H, alkyl or aryl, in the presence of a hydrolytic enzyme, and wherein the opposite enantiomers may alternatively be used.