EDUCATION

1998.9 - 2002.6     Southwest China Normal University, B. S.
 
2002.9 - 2007.12   Nankai University, SKLEOC, Ph. D.
 
2008.1 - Now          Rutgers, the State University of New Jersey
CONTACT 

Tel: 732-445-1454(Lab)
 
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Address: 192A, Cedar Lane, Highland Park, New Jersey 08904

DISSERTATION

Abstract 

Chiral amine is an essential structural unit in natural products and a key function group in many biologically active molecules. The catalytic asymmetric hydrogenation of functionalized enamines such as a- and b-N-acylamino acrylates, and enamides is one of the most efficient methods to form chiral primary and secondary amine derivatives. However, very few enantioselective methods have been reported for the synthesis of chiral tertiary amines. In this dissertation, we focus on the asymmetric hydrogenation of unprotected enamines using monodentate phosphorus ligands containing 1,1'-spirobiindane backbone.

The synthesis of phosphonite ligands containing a 1,1a-spirobiindane scaffold and their application in Rh-catalyzed asymmetric hydrogenation of unprotected acyclic N,N-dialkylenamines. The spiro phosphonite ligand was found to be a good ligand for this reaction. Using I₂ and acetic acid as additives, the reaction can proceed under mild conditions in 100% conversion, providing the corresponding tertiary amines in high yields with excellent enantioselectivities (up to 99.9% ee). This is the best result reported in literature.

For the first time, the highly enantioselective Ir-catalyzed asymmetric hydrogenation of unprotected cyclic enamines was realized by using Ir/(S,R,R)-SIPHOS-PE complex as catalyst and I₂ as additive, affording the cyclic tertiary amines in excellent enantioselectivities (up to 96% ee). 

Furthermore, the Ir-catalyzed asymmetric hydrogenation of the unprotected acyclic enamines was also investigated. Although the most results were not better than those obtained by the Rh catalyst, the enantioselectivities of up to 98% ee have been achieved in the hydrogenation of orth-substituent substrates, which is higher than those obtained by Rh catalyst.

Keywords: unprotected enamines, spiro phosphonite, rhodium, iridium, asymmetric hydrogenation, catalysis.

PUBLICATION

1. Pu-Cha Yan, Jian-Hua Xie, Guo-Hua Hou, Li-Xin Wang, Qi-Lin Zhou*, Enantioselective synthesis of chiral tetrahydroisoquinolines by iridium-catalyzed asymmetric hydrogenation of enamines, Adv. Synth. Catal. 2009, 351, 3243-3250.

2. Guo-Hua Hou, Jian-Hua Xie, Pu-Cha Yan, Qi-Lin Zhou*, Iridium-catalyzed asymmetric hydrogenation of cyclic enamines, J. Am. Chem. Soc. 2009, 131, 1366-1367.

3.Wen-Jian Shi, Qi Zhang, Jian-Hua Xie, Shou-Fei Zhu, Guo-Hua Hou, Qi-Lin Zhou*, Highly enantioselective hydrovinylation of α-alkyl vinylarenes. An approach to the construction of all-carbon quaternary stereocenters, J. Am. Chem. Soc. 2006, 128, 2780-2781.

4.Guo-Hua Hou, Jian-Hua Xie, Lin-Xin Wang, Qi-Lin Zhou*, Highly efficient Rh(I)-catalyzed hydrogenation of enamines using monodentate spiro phosphonite ligands, J. Am. Chem. Soc. 2006, 128, 11774-11775.

5.Xu Cheng, Guo-Hua Hou, Jian-Hua Xie, Qi-Lin Zhou*, Synthesis and optical resolution of 9,9'-spirobifluorene-1,1'-diol, Org. Lett. 2004, 6, 2381-2383.

6.Yu Fu, Guo-Hua Hou, Jian-Hua Xie, Liang Xing, Li-Xin Wang, Qi-Lin Zhou*, Synthesis of monodentate chiral spiro phosphonites and the electronic effect of ligand in asymmetric hydrogenation, J. Org. Chem. 2004, 69, 8157-8160.

7.Xun-Xiang Guo, Jian-Hua Xie, Guo-Hua Hou, Wen-Jian Shi, Li-Xin Wang, Qi-Lin Zhou*, Asymmetric palladium-catalyzed hydrosilylation of styrenes using efficient chiral spiro phosphoramidite ligands, Tetrahedron: Asymmetry 2004, 15, 2231-2234.