Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids

doi:10.3390/90500349

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Molecules 2004, 9(5), 349-364; doi:10.3390/90500349

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Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids

Rafael Chinchilla, Patricia Mazón and Carmen Nájera*

Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain

* Author to whom correspondence should be addressed.

Received: 2 March 2004 / Accepted: 22 March 2004 / Published: 30 April 2004

(This article belongs to the Special Issue Carbanion chemistry from Carboxylic acids in honor of Prof. Ramón Mestres on his 65th anniversary)

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Abstract: Alkaloids such as cinchonidine, quinine and N-methylephedrine have been N-alkylated using polymeric benzyl halides or co-polymerized and then N-alkylated, thus affording a series of polymer-supported chiral ammonium salts which have been employed as phase-transfer catalysts in the asymmetric benzylation of an N-(diphenylmethylene)glycine ester. These new polymeric catalysts can be easily recovered by simple filtration after the reaction and reused. The best ee’s were achieved when Merrifield resin-anchored cinchonidinium ammonium salts were employed.

Keywords: Amino acids; asymmetric synthesis; phase-transfer catalysis; chiral ammonium salts.

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MDPI and ACS Style

Chinchilla, R.; Mazón, P.; Nájera, C. Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids. Molecules 2004, 9, 349-364.

AMA Style

Chinchilla R, Mazón P, Nájera C. Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids. Molecules. 2004; 9(5):349-364.

Chicago/Turabian Style

Chinchilla, Rafael; Mazón, Patricia; Nájera, Carmen. 2004. "Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids." Molecules 9, no. 5: 349-364.

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