Preparation method of chiral multiple substituted tetrahydropyran
AssigneeNational Taiwan Normal University
InventorsKwunmin Chen, Ramani Gurubrahamam, You-Song Cheng
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Abstract
An organocatalytic kinetic resolution of racemic secondary nitroallylic alcohols via Michael/acetalization sequence to give fully substituted tetrahydropyranols is described. The process affords the products with high to excellent stereoselectivities. The highly enantioenriched, less reactive (S)-nitroallylic alcohols were isolated with good to high chemical yields. The synthetic application of the resolved substrate is shown toward the synthesis of enantioenriched (+)-(2S,3R)-3-amino-2-hydroxy-4-phenylbutyric acid.
Claims14
A preparation method of a chiral multiple substituted tetrahydropyran derivative which comprises:
- subjecting the compound represented by formula (I) and the compound represented by formula (II) to Michael addition/acetalization reaction in the presence of an organic catalyst, a solvent and an acidic additive to form a crude product;
- and
- isolating the crude product by column chromatography to obtain a chiral multiple substituted tetrahydropyran derivative and to isolate a (S)-configuration compound represented by formula (II),
- wherein, R is a C1-4 alkyl, or a C1-4 alkoxy substituted with a C6-10 aryl;
- Ar is an unsubstituted C6-10 aryl, a C4-10 heterocycloaryl, or a C6-10 aryl or a C4-10 heterocycloaryl substituted with at least one substituent selected from a group consisting of a halogen, a C1-4 alkyl, a C1-4 alkoxy, a C6-10 aryl, a C6-10 aryl C1-4 alkoxy, and a nitro;
- and the chiral multiple substituted tetrahydropyran derivative is represented by formula (III),
- wherein R and Ar are of same definition as those of formula (I) and formula (II).
Dependencies are inferred from the claim text.