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Asymmetric 1,4‐Addition of Diethylzinc to Cyclic Enones Catalyzed by Cu(I)‐Chiral Sulfonamide‐Thiophosphoramide Ligands and Lithium Salts
Author(s) -
Shi Min,
Zhang Wen
Publication year - 2005
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200404321
Subject(s) - diethylzinc , chemistry , ligand (biochemistry) , sulfonamide , chiral ligand , denticity , catalysis , medicinal chemistry , enantioselective synthesis , lithium (medication) , chloride , stereochemistry , combinatorial chemistry , organic chemistry , crystal structure , receptor , medicine , biochemistry , endocrinology
The chiral sulfonamide‐thiophosphoramide ligand L1 , prepared from the reaction of (1 R ,2 R )‐(−)‐1,2‐cyclohexanediamine with diphenylthiophosphoryl chloride and p ‐toluenesulfonyl chloride, was used as a chiral ligand in Cu(MeCN) 4 ClO 4 ‐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 1 H NMR, 31 P 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.