摘要
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The chiral sulfonamide-thiophosphoramide ligand L1, prepared from the reaction of (1R,2R)(-)-1,2-cyclohexanediamine with diphenylthiophosphoryl chloride and p-toluenesulfonyl chloride, was used as a chiral ligand in Cu(MeCN)(4)ClO...
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The chiral sulfonamide-thiophosphoramide ligand L1, prepared from the reaction of (1R,2R)(-)-1,2-cyclohexanediamine with diphenylthiophosphoryl chloride and p-toluenesulfonyl chloride, was used as a chiral ligand in Cu(MeCN)(4)ClO4-promoted catalytic asymmetric addition of diethylzinc to cyclic enones using LiCl as an additive in which up to 90% ee can be realized under mild conditions within 0.5 h. This chiral ligand is stable and recoverable after usual work-up and can be reused in the same catalytic asymmetric reaction. Moreover, it was found that this series of chiral ligands represents a type of S,O-bidentate ligands on the basis of H-1 NMR, P-31 NMR and 13 C NMR spectroscopic investigations. The linear effect of ligand ee and product ee further revealed that the active species is a monomeric Cu(I) complex bearing a single ligand.
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