Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions

doi:10.3390/molecules15118305

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Molecules 2010, 15(11), 8305-8326; doi:10.3390/molecules15118305

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Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions

Kohzo Yoshida, Tsubasa Inokuma, Kiyosei Takasu and Yoshiji Takemoto*

Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan

* Author to whom correspondence should be addressed.

Received: 13 October 2010; in revised form: 8 November 2010 / Accepted: 12 November 2010 / Published: 15 November 2010

(This article belongs to the Special Issue Bifunctional Catalysis)

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Abstract: Organoammonium salts composed of a Brønsted acid and an anilinothiourea promoted the Michael addition of β-keto esters and α,β-unsaturated aldehydes in the presence of primary amines to give functionalized 1,4-dihydropyridines enantioselectively. With the use of the different Brønsted acids such as DFA and HBF₄ with the same bifunctional thiourea, both enantiomers of 4-substituted 1,4-dihydropyridine were synthesized from the same starting materials.

Keywords: bifunctional thiourea-ammonium salt; aminothiourea; Brønsted acid; 1,4-dihydropyridines; Michael addition; a,b-unsaturated aldehydes; b-keto esters

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Cite This Article

MDPI and ACS Style

Yoshida, K.; Inokuma, T.; Takasu, K.; Takemoto, Y. Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions. Molecules 2010, 15, 8305-8326.

AMA Style

Yoshida K, Inokuma T, Takasu K, Takemoto Y. Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions. Molecules. 2010; 15(11):8305-8326.

Chicago/Turabian Style

Yoshida, Kohzo; Inokuma, Tsubasa; Takasu, Kiyosei; Takemoto, Yoshiji. 2010. "Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions." Molecules 15, no. 11: 8305-8326.

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