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1997.9 - 2001.6 Nankai University, College of Chemistry, B. S.
2001.9 - 2007.6 Nankai University, SKlEOC, Ph. D.
Address: KTH - The Royal Institute of Technology, Department of Chemistry, Organic Chemistry, TEKNIKRINGEN 36, 10044 STOCKHOLM, Sweden.
The ring-opening of epoxide by nucleophile is one of the basic method to obtain alcohol compounds with multiple chiral centers. Espescially when orgnaometallics reagents are applied as nuleophiles, new carbon-carbon bonds are constructed simultaneously. In this transformation, the asymmetric ring-opening of oxabicylic alkenes provides methodology to form cyclic alcohol, which is of high importance in organic synthesis. However, most organometallic reagents applied in the metal-catalyzed ring opening of oxabicylic alkenes mainly are organozinc, organoaluminum and organoboric reagents. In constrast, Grignard reagent, the most popular organometallic reagent in organic synthesis, is barely applied in this reaction. In this dissertation, we demonstrate the successful ring-opening of oxabicyclic alkenes with Grignard reagents in the presence of copper complex of monodentate spiro phosphorous ligands.
Firstly, the monodentate spiro phosphoramidite ligand (S,SS)-SIPHOS-PE was chosen as chiral ligand in copper-catalyzed asymmetric ring-opening of oxabicyclic alkenes with Grignard reagent. The reaction can take place at a mild condition, and the ring opening products-alkylated cyclic alcohols were attained in good yields, excellent anti-selectivities and good enantioselectivites. This is the first example of enantioselective ring-opening reaction of oxabicylic alkenes with Grignard reagents.
For obtaining high reactivity and high enantioselectivity, we developed a series of electron-rich monodentate spiro phosphorus ligands SITCPs. Ligands SITCP show very high reactivities and enantioselectivities in the ring opening reaction of oxabicyclic alkenes with Grignard reagents. Under the optimized reaction conditions, the catalyst Cu/SITCPs can perform the reaction at a low catalyst loading ( s/c up ot 10,000) and in high enantioselectivities ( ee up to 98 %). This is the best result reported in this reaction.
Key word: asymmetric-ring-opening, Grignard reagent, oxabicyclic alkenes, copper-catalysis, phosphorous ligand.
1. Wei Zhang, Shou-Fei Zhu, Xiang-Chen Qiao, Qi-Lin Zhou*, Highly enantioselective copper-catalyzed ring opening of oxabicyclic alkenes with Grignard reagents, Chem. Asian J. 2008, 3, 2105-2111.
2.Bin Liu, Shou-Fei Zhu, Wei Zhang, Chao Chen, Qi-Lin Zhou*, Highly enantioselective insertion of carbenoids into N-H bonds catalyzed by copper complexes of chiral spiro bisoxazolines, J. Am. Chem. Soc. 2007, 129, 5834-5835.
3.Jun Zhong, Jian-Hua Xie, Ai-E Wang, Wei Zhang, Qi-Lin Zhou*, Highly efficient triaryl phosphine-functionalized N-heterocyclic carbene ligands for hydroarylation reaction, Synlett 2006, 1193-1196.
4.Wei Zhang, Li-Xin Wang, Wen-Jian Shi, Qi-Lin Zhou*, Copper-catalyzed asymmetric ring opening of oxabicyclic alkenes with Grignard reagents, J. Org. Chem. 2005, 70, 3734-3736.
5.Jun-An Ma, Jun-Hua Wan, Yi-Bo Zhou, Li-Xin Wang, Wei Zhang, Qi-Lin Zhou*, Chiral dihydrodinaphthazepinyl-oxazolines as ligands in the enantioselective cyclopropanation of olefins, J. Mol. Catal. Α: Chem. 2003, 196, 109-115.
6.Jun-An Ma, Li-Xin Wang, Wei Zhang, Qi-Lin Zhou*, Synthesis of imine-amine type of chiral ligands and their application in asymmetric cyclopropanation of olefins with diazoacetates, Tetrahedron: Asymmetry 2001, 12, 2801-2804.