Synthesis of New Chiral Phase Transfer Catalysts and their Application in the Asymmetric Alkylation of Glycine Derivatives

Review Article

Austin J Anal Pharm Chem. 2014;1(1): 1003.

Synthesis of New Chiral Phase Transfer Catalysts and their Application in the Asymmetric Alkylation of Glycine Derivatives

Dong Xiaoyang, Wang Zhiyu, Huang Daorui, Xu Pei and Dai Zhenya*

Department of Pharmaceutical Chemistry, China Pharmaceutical University, China

*Corresponding author: :Dai Zhenya, Department of Pharmaceutical Chemistry, China Pharmaceutical University, School of Pharmacy, 24 Tongjiaxiang, Nanjing, P. R. China.

Received: June 09, 2014; Accepted: June 26, 2014; Published: June 28, 2014

Abstract

A new type of chiral phase transfer catalysts were synthesized and applied in the asymmetric alkylation of glycine derivatives with high yields and moderate to high ees (58-88%).

Keywords: Chiral phase transfer catalysts; Asymmetric alkylation; Glycine derivatives

Chiral unnatural amino acids play an important role in pharmaceutical industry and the synthesis of them are of great importance. The asymmetric alkylation of glycine derivatives with chiral phase transfer catalysts is one of the most important methods to prepare the chiral unnatural amino acids [1]. In recent years, chiral phase transfer catalysts derived from cinchona alkaloids have been a hotspot in asymmetric catalysis. Up to date, such kind catalysts can be divided into three generations [2-5]. As is shown in Figure 1: the first generation: R=H, Ar=Phenyl; the second generation: R=Allyl, Ar=Phenyl; and the third generation: R=Alkyl, Ar=Anthracyl. Deng et al. reported that the second generation of the catalysts could catalyze the asymmetric Darzens reaction with high yield and excellent enantioselectivity [6], Waser et al. reviewed the catalyzed asymmetric reactions catalyzed by the bifunctional ammonium catalysts [7], Maruoka et al. reviewed the asymmetric phase transfer catalysis with choral ammonium catalysts derived from cinchona and choral C2-type ammonium catalysts [8].