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鄢明, Michael P. Doyle* and Ming Yan
Tetrahedron Letters 43(2002)5929-5931,-0001,():
-1年11月30日
The chiral dirhodium(Ⅱ) catalyst Rh2(MEAZ)4 increases diastereocontrol for intermolecular O-H insertion reactions of diazo esters having a chiral auxiliary over that achieved with Rh2(OAc)4.
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鄢明, Ming Yan, * Wei-Jie Zhao, Dan Huang and Shun-Jun Ji
Tetrahedron Letters 45(2004)6365-6367,-0001,():
-1年11月30日
The reaction of aryldiazoacetates with enamines catalyzed by copper and rhodium complexes provided c-ketoesters in good yields. Careful analysis of the crude reaction mixture revealed a substituted enamine as the primary product, which was hydrolyzed over silica gel to give a c-ketoester as the final product. A reaction mechanism involving nucleophilic addition of an enamine to a metal carbene and subsequent hydrogen transfer was proposed.
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鄢明, Michael P. Doyle* and Ming Yan
J. Org. Chem. 2002, 67, 602-604,-0001,():
-1年11月30日
Diazo coupling reactions are capable of forming E,E,E-trienes from cinnamaldehydes in good yield. An efficient methodology is reported for the production of styryldiazomethanes that are subsequently used with catalysis for coupling and for cyclopropanation. A vast difference in product selectivity is seen with styryldiazomethane generated from the corresponding hydrazone via manganese dioxide oxidation and that formed in situ by treatment of the tosylhydrazone sodium salt of cinnamaldehyde with transition metal catalysts. This observation impacts understanding of the reaction mechanism for diazo decomposition.
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鄢明, Ming Yan, Zhong-Yuan Zhou and Albert S. C. Chan*
Chem. Commun., 2000, 115-116,-0001,():
-1年11月30日
Highly enantioselective conjugate addition of diethylzinc to a, β-unsaturated lactones was achieved by using chiral diphosphite-copper catalysts; the structure of a chiral diphosphite-copper (I) catalyst was determined by single crystal X-ray diffraction.
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鄢明, Ming Yan and Albert S. C. Chan *
Tetrahedron Letters 40(1999)6645-6648,-0001,():
-1年11月30日
A series of C2-symmetric aryl diphosphites based on chiral binaphthol were prepared and their copper complexes were found to be efficient catalysts for the conjugate addition of diethylzinc to cyclic enones. Good enantioselectivities (up to 89.8 and 88.7% ee, respectively) were obtained in the conjugate addition of diethylzinc to 2-cyclohexenonc and 2-cyclopcntenone.
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