ChemInform Abstract: Crystallization-Induced Dynamic Resolution and Nucleophilic Substitutions of...

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2008 Diastereoselective syntheses O 0031 Crystallization-Induced Dynamic Resolution and Nucleophilic Substitutions of N-(S)-(1-Phenylethyl)-α-chloro-α-phenyl Acetamide for the Preparation of N-Carboxyalkylated Flavone. — Epimerization in the presence of NH4OH and selec- tive crystallization in the presence of H2O leads to a stereoselective formation of the title amide (II) which reacts with nucleophiles. Under basic conditions, epimerization is observed [cf. formation of (IV)]. However, with Ac-SK(V), the reaction proceeds stereoselectively and the thiol (VII) can be used as chiral auxiliary for the preparation of enantioenriched flavones such as (XII). — (LEE, M. H.; KANG, K. H.; LEE, Y. M.; KIM, D.; PARK*, Y. S.; Bull. Korean Chem. Soc. 29 (2008) 5, 1075-1078; Dep. Chem., Kon-Kuk Univ., Kwangjinku, Seoul 143-701, S. Korea; Eng.) — K. Woydowski 41- 025

Transcript of ChemInform Abstract: Crystallization-Induced Dynamic Resolution and Nucleophilic Substitutions of...

2008

2008.41.fm Page 25 Monday, September 8, 2008 9:22 AM

Diastereoselective synthesesO 0031 Crystallization-Induced Dynamic Resolution and Nucleophilic Substitutions

of N-(S)-(1-Phenylethyl)-α-chloro-α-phenyl Acetamide for the Preparation of N-Carboxyalkylated Flavone. — Epimerization in the presence of NH4OH and selec-tive crystallization in the presence of H2O leads to a stereoselective formation of the title amide (II) which reacts with nucleophiles. Under basic conditions, epimerization is observed [cf. formation of (IV)]. However, with Ac-SK(V), the reaction proceeds stereoselectively and the thiol (VII) can be used as chiral auxiliary for the preparation of enantioenriched flavones such as (XII). — (LEE, M. H.; KANG, K. H.; LEE, Y. M.; KIM, D.; PARK*, Y. S.; Bull. Korean Chem. Soc. 29 (2008) 5, 1075-1078; Dep. Chem., Kon-Kuk Univ., Kwangjinku, Seoul 143-701, S. Korea; Eng.) — K. Woydowski

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