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US 4,000,169 AGranted
Asymmetric synthesis of optically active compounds
AssigneeHoffmann-La Roche Inc.
InventorsKa-Kong Chan, Gabriel Saucy
Life of this patent
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Abstract
Asymmetric synthesis of optically active 3,7,11-trimethyl-dodecan-1-ol, an intermediate for producing optically active vitamin E, from isovaleraldehyde or prenal including intermediates in this synthesis.
Claims13
A process for preparing a compound of the formula:
- ##STR34## wherein R.sub.6 is hydrogen, lower alkoxy, or, ##STR35## and n is an integer of from 0 to 1;
- A and B are individually hydrogen, or taken together form a carbon to carbon bond;
- R.sub.7, R.sub.8 and R.sub.9 are lower alkyl and n is an integer of from 0 to 1;
- comprising subjecting an optically active isomer of the formula ##STR36##
- wherein n, A and B are as above;
- one of R.sub.1 and R.sub.2 is hydrogen and the other is hydroxy, with the proviso that when R.sub.1 is hydroxy, the 2-3 double bond has a cis configuration, and when R.sub.1 is hydrogen, the 2-3 double bond has a trans configuration;
- free of other optically active isomers to Claisen rearrangement by reaction under Claisen conditions with a rearrangement agent selected from the group consisting of compounds of the formula:
- CH.sub.2 =CH-OR.sub.10 ##STR37##
- wherein R.sub.10 is lower alkyl, X is halogen and R.sub.7 and R.sub.8 are as above.
6 more elements
A compound of the formula:
- ##STR39##
- wherein R.sub.6 is hydrogen, hydroxy, ##STR40##
- n is an integer from 0 to 1;
- A and B are individually hydrogen or taken together form a carbon to carbon bond;
- R.sub.7, R.sub.8 and R.sub.9 are lower alkyl.
2 more elements
The compound of the formula:
- ##STR41##
- wherein A and B are individually hydrogen or taken together form a carbon to carbon bond, R.sub.6 ' is lower alkoxy and n is an integer of from 0 to 1.
Dependencies are inferred from the claim text.