Process Development on the Preparation of <i>trans</i>-(+)-2-Methylaminocyclohexanol:  A Fascinating Resolution Example

Lu, Xinbo; Xu, and Zunle; Tang, Guangming

doi:10.1021/op0000428

Cited by 6 publications

(2 citation statements)

References 6 publications

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“…This result is in agreement with observations by Noyori for the corresponding primary amino alcohol 48c. With regard to the highly selective ligand 20 , N -methyl-substituted aminocyclohexanol (1 S ,2 S )- 24 was prepared by resolution of the racemate with ( R )-mandelic acid affording the enantiopure material after three recrystallizations in 46% overall yield . By its application in the test reaction, a 94% conversion of 22a to the product alcohol was achieved within 1 h, and the product had 68% ee (entry 3).…”

Section: Resultssupporting

confidence: 89%

Resolution of Racemic 2-Aminocyclohexanol Derivatives and Their Application as Ligands in Asymmetric Catalysis

et al. 2006

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A preparatively easy and efficient protocol for the resolution of racemic 2-aminocyclohexanol derivatives is described, delivering both enantiomers with >99% enantiomeric excess (ee) by sequential use of (R)- and (S)-mandelic acid. A simple aqueous workup procedure permits the isolation of the amino alcohols in analytically pure form and the almost quantitative recovery of mandelic acid. Debenzylation of enantiopure trans-2-(N-benzyl)amino-1-cyclohexanol by hydrogenation and subsequent derivatization give access to a broad variety of diversely substituted derivatives. Furthermore, the corresponding cis isomers are readily available. Applications of these optically active aminocyclohexanols in catalyzed asymmetric phenyl transfer reactions to benzaldehydes and transfer hydrogenations of aryl ketones lead to products with up to 96% ee.

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Section: Resultssupporting

confidence: 89%

Resolution of Racemic 2-Aminocyclohexanol Derivatives and Their Application as Ligands in Asymmetric Catalysis

et al. 2006

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“…Then 80 μL of the combined product diethyl ether solution (1.2 mL) was used to interact with the fluorescent probe rac - 2 for fluorescence measurement. For chiral HPLC analysis, the product 3 was in situ derivatized by reaction with m -toluoyl chloride . The amino alcohol crude product 3 was obtained by diethyl ether (2 × 2 mL) extraction from the reaction solid mixtures followed by rotary evaporation.…”

Section: Methodsmentioning

confidence: 99%

Enantioselective Sensing in the Fluorous Phase for Catalyst Screening: Application of a Racemic Fluorescent Probe

Marks

Wang

et al. 2021

J. Org. Chem.

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A perfluoroalkyl ketone-based molecular probe was found to show highly enantioselective fluorescent enhancement in the fluorous phase when treated with an amino alcohol generated from the asymmetric reaction of a meso-epoxide with an alkyl amine. The two enantiomeric probes (R)and (S)-2 were used to screen catalysts for this asymmetric reaction. The use of the probe in the fluorous phase allowed the fluorescent sensing of the products to be conducted away from the other reaction components with minimized interference. It was further found that when (R)-or (S)-2 was used to determine the enantiomeric composition of the amino alcohol product, there was a large nonlinear effect. That is, only when one enantiomer of the substrate was in excess was there a large fluorescence enhancement for the chirality-matched probe−substrate interaction. This allowed the racemic probe rac-2 to be used to evaluate the asymmetric induction in the catalyst screening. The catalyst screening using the fluorescent probes led to the discovery of a more enantioselective and efficient method for the desymmetrization of 1,2-epoxycyclohexane with i PrNH 2 to form the corresponding chiral amino alcohol. This work presents a novel method to conduct catalyst screening for asymmetric synthesis and has potential to become a high-throughput process.

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Synthesis and Resolution of Racemic Trans ‐2‐( N ‐Benzyl)Amino‐1‐Cyclohexanol: Enantiomer Separation by Sequential Use of ( R )‐ and ( S )‐Mandelic Acid

Schiffers

Bolm

2008

Organic Syntheses

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Cyclohexene oxide Benzylamine ( S )‐(+)‐Mandelic acid ( R )‐(−)‐Mandelic acid ( S )‐Mandelic salt of (1 R , 2R)‐trans‐ ( N‐ benzyl)amino‐1‐cyclohexanol ( R )‐Mandelic salt of (1 S , 2S)‐trans‐ ( N‐ benzyl)amino‐1‐cyclohexanol (1 R,2R )‐ trans ‐2‐( N ‐Benzyl)amino‐1‐cyclohexanol (1 S,2S )‐ trans ‐2‐( N ‐Benzyl)amino‐1‐cyclohexanol

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Process Development on the Preparation of trans-(+)-2-Methylaminocyclohexanol: A Fascinating Resolution Example

Cited by 6 publications

References 6 publications

Resolution of Racemic 2-Aminocyclohexanol Derivatives and Their Application as Ligands in Asymmetric Catalysis

Resolution of Racemic 2-Aminocyclohexanol Derivatives and Their Application as Ligands in Asymmetric Catalysis

Enantioselective Sensing in the Fluorous Phase for Catalyst Screening: Application of a Racemic Fluorescent Probe

Synthesis and Resolution of Racemic Trans ‐2‐( N ‐Benzyl)Amino‐1‐Cyclohexanol: Enantiomer Separation by Sequential Use of ( R )‐ and ( S )‐Mandelic Acid

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