Lithium Hydroxide → (1R,2R)-2-(4-bromophenyl)Cyclopropanecarboxylic acid

HRID 1392696Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1392696
[N+](=CC([O-])=O)=[N-].[Br:7][C:8]1[CH:13]=[CH:12][C:11]([C@@H:14]2[CH2:16][C@H:15]2[C:17]([O:19][CH2:20][CH3:21])=[O:18])=[CH:10][CH:9]=1.BrC1C=CC(C=C)=CC=1.[Li+].[OH-]>>[Br:7][C:8]1[CH:9]=[CH:10][C:11]([C@@H:14]2[CH2:16][C@H:15]2[C:17]([OH:19])=[O:18])=[CH:12][CH:13]=1.[Br:7][C:8]1[CH:9]=[CH:10][C:11]([C@H:14]2[CH2:16][C@H:15]2[C:17]([O:19][CH2:20][CH3:21])=[O:18])=[CH:12][CH:13]=1

Komponenten

6

Edukt 4

HCID 3939Lithium HydroxideHCID 162634-BromostyreneHCID 21863207DiazoacetateHCID 66578655ethyl (1R,2R)-2-(4-bromophenyl)cyclopropanecarboxylate

Produkt 2

HCID 12586658(1R,2R)-2-(4-bromophenyl)Cyclopropanecarboxylic acidHCID 66578128ethyl (1R,2S)-2-(4-bromophenyl)cyclopropane-1-carboxylate

Versuchsvorschrift

Another alternative is an enantioselective cyclopropanation using for example a bis-oxazoline chiral ligand/copper complex and diazoacetate (Evans et al. J. Am. Chem. Soc. 1991, 113, 726) to prepare optically active ethyl 2-(trans)-(4-bromophenyl)cyclopropanecarboxylate from 4-bromostyrene. Selective hydrolysis of the mixture of cis and trans isomer with LiOH (1 eq based on the trans ester) gave 2-(trans)-(4-bromophenyl)cyclopropanecarboxylic acid and ethyl 2-(cis)-(4-bromophenyl)cyclopropanecarboxylate which can be used in EXAMPLE 8.

Aufarbeitung

  1. customhydrolysis of the mixture of cis and trans

Quellen und Nachweise

ORD-Eintrag
ord-46285eeb155846258f7b3e353f705420
Quelldatensatz
uspto-grants-2008_03
Patentnummer
US07342024B2

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