Process for producing optically active 2-norbornanone
AssigneeKuraray Co., Ltd.
InventorsMasahiro Torihara, Yoshin Tamai
Life of this patent
Estimating the term…
Abstract
An optically active 5-methylenedioxolan-4-one derivative is subjected to Diels-Alder reaction with cyclopentadiene, and the resulting Diels-Alder reaction product is hydrolyzed to convert it into an optically active 2-hydroxynorbornene-2-carboxylic acid, which is then subjected to catalytic hydrogenation to form an optically active 2-hydroxynorbornane-2-carboxylic acid. The hydroxycarboxylic acid is subjected to oxidative decarboxylation to obtain an optically active 2-norbornanone.
Claims7
A process for producing an optically active 2-norbornanone represented by Formula (1a) or (1b):
- ##STR17## said process comprising the steps of;
- a) allowing an optically active dioxolan-4-one derivative represented by the Formula (2*) ##STR18## wherein R.sup.1 represents a substituted or unsubstituted alkyl group or aryl group, and * represents an asymmetric carbon atom;
- to react with cyclopentadiene to form a compound represented by formula (3a) or (3b):
- ##STR19## wherein R.sup.1 and * are as defined in Formula (2*);
- b) hydrolyzing the compound of Formula (3a) or (3b) obtained in the step a), to convert it into an optically active 2-hydroxynorbornene-2-carboxylic acid represented by Formula (4a) or (4b):
- ##STR20## c) subjecting the compound of Formula (4a) or (4b) obtained in the step b), to catalytic hydrogenation to form a compound represented by the Formula (5a) or (5b):
- ##STR21## d) subjecting the compound of Formula (5a) or (5b) obtained in the step c), to oxidative decarboxylation with a hypohalogenite to form the optically active 2-norbornanone of Formula (1a) or (1b).
A process for producing an optically active 2-hydroxynorbornene-2-carboxylic acid represented by Formula (4a) or (4b ):
- ##STR22## said process comprising the steps of;
- a. allowing an optically active dioxolan-4-one derivative represented by Formula (2*) ##STR23## wherein R represents a substituted or unsubstituted alkyl group or aryl group, and * represents an asymmetric carbon atom;
- to react with cyclopentadiene to form a compound represented by Formula (3a) or (3b):
- ##STR24## wherein R and * are as defined in Formula (2*);
- b. hydrolyzing the compound of Formula (3a) or (3b) obtained in the step a., to convert it into the optically active 2-hydroxynorbornene-2-carboxylic acid of Formula (4a) or (4b).
A process for producing 2-norbornanone represented by Formula (1):
- ##STR25## said process comprising the step of subjecting 2-hydroxynorbornane-2-carboxylic acid represented by Formula (5):
- ##STR26## to oxidative decarboxylation in the presence of a hypohalogenite to obtain the 2-norbornanone of Formula (1).
A process for producing a 5-methylene-1,3-dioxolan-4-one represented by Formula (2):
- ##STR27## wherein R.sup.1 represents a substituted or unsubstituted alkyl group or aryl group;
- said process comprising the step of allowing a 5-halogeno-5-methyl-1,3-dioxolan-4-one derivative represented by Formula (6):
- ##STR28## wherein R.sup.1 is as defined in Formula (2), and X represents a halogen atom;
- to react with a tertiary amine represented by Formula (7):
- ##STR29## wherein R.sup.2 R.sup.3 and R.sup.4 each independently represent an alkyl group having 4 to 12 carbon atoms;
- to convert said derivative into the compound of Formula (2).
Dependencies are inferred from the claim text.