Optically active 4-hydroxy-2-cyclopentenones, and their production
AssigneeSumitomo Chemical Company, Limited
InventorsMasayoshi Minai, Tadashi Katsura
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Abstract
A process for preparing an optically active 4-hydroxy-2-cyclopentenone of the formula: ##STR1## wherein R.sub.1 is a hydrogen atom or a methyl group, R.sub.2 is an alkyl group, an alkenyl group or an alkynyl group and the asterisk (*) indicates an asymmetric configuration, which comprises subjecting an optically active 4-cyclopentenone-alcohol of the formula: ##STR2## wherein R.sub.1 and R.sub.2 are each as defined above, the asterisk (*) indicates an asymmetric configuration and the substituents R.sub.1 and R.sub.2 take a cis-configuration to rearrangement while maintaining the original steric configuration.
Claims27
A process for preparing an optically active 4-hydroxy-2-cyclopentenone of the formula:
- ##STR9## wherein R.sub.1 is a hydrogen atom or a methyl group, R.sub.2 is an alkyl group of not more than 12 carbon atoms, an alkenyl group of not more than 12 carbon atoms or an alkenyl group of not more than 12 carbon atoms and the asterisk (*) indicates an asymmetric configuration, which comprises subjecting a racemic or optically active 4-cyclopentenone ester of the formula:
- ##STR10## wherein R.sub.1 and R.sub.2 are each as defined above, R is a lower alkanoyloxy group and the substitutents R.sub.1 and R.sub.2 take a cis-configuration to asymmetric hydrolysis with an enzyme or microorganism capable of hydrolyzing the same, and treating the resultant optically active 4-cyclopentenone-alcohol of the formula:
- ##STR11## wherein R.sub.1 and R.sub.2 are each as defined above, the asterisk (*) indicates an asymmetric configuration and the substituents R.sub.1 and R.sub.2 take a cis-configuration with a catalyst selected from the group consisting of organic tertiary amines, metal oxides, inorganic bases and basic buffers at a temperature of -20.degree. to 130.degree. C., whereby the optically active 4-cyclopentenone-alcohol (II) is rearranged to the optically active 4-hydroxy-2-cyclopentenone (I) while maintaining the original steric configuration.
A process for preparing an optically active 4-hydroxy-2-cyclopentenone of the formula:
- ##STR14## wherein R.sub.1 is a hydrogen atom or a methyl group, R.sub.2 is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, iso-butyl, n-pentyl, isopentyl, n-hexyl, cyclopentyl, cyclohexyl, allyl, 2-butenyl, 3-butenyl, 2-pentynyl, n-hexyl, n-heptyl, 2-pentenyl, 3-hexynyl, propargyl or 2-methylallyl, and the asterisk (*) indicates an asymmetric configuration, which comprises subjecting a racemic or optically active 4-cyclopentenone ester of the formula:
- ##STR15## wherein R.sub.1 and R.sub.2 are each as defined above, R is a lower alkanoyloxy group and the substituents R.sub.1 and R.sub.2 take a cis-configuration to asymmetric hydrolysis with an enzyme or microorganism capable of hydrolyzing the same, and treating the resultant optically active 4-cyclopentenone-alcohol of the formula:
- ##STR16## wherein R.sub.1 and R.sub.2 are each as defined above, the asterisk (*) indicates an asymmetric configuration and the substitutents R.sub.1 and R.sub.2 take a cis-configuration with a catalyst selected from the group consisting of organic teritiary amines, metal oxides, inorganic bases and basic buffers at a temperature of -20.degree. to 130.degree. C., whereby the optically active 4- cyclopentenone-alcohol (II) is rearranged to the optically active 4-hydroxy-2-cyclopentenone (I) while maintaining the original steric configuration.
Dependencies are inferred from the claim text.