Copper hydride-catalyzed conjugate reduction-intermolecular aldol addition domino reactions were realized using α,β-unsaturated carboxylates as hydride acceptors and a silane as the reducing reagent. High diastereos...Copper hydride-catalyzed conjugate reduction-intermolecular aldol addition domino reactions were realized using α,β-unsaturated carboxylates as hydride acceptors and a silane as the reducing reagent. High diastereoselec- tivities were achieved with 4,5-bis（diphenylphosphino）-9,9-dimethylxanthene as the ligand and tert-butyl acrylate as the hydride acceptor.展开更多
Intramolecular conjugate reduction-aldol addition reactions of β＇-oxoalkyl a,fl-unsaturated carboxylates were performed in the presence of copper catalysts generated in situ from copper salts, phosphine ligands and ...Intramolecular conjugate reduction-aldol addition reactions of β＇-oxoalkyl a,fl-unsaturated carboxylates were performed in the presence of copper catalysts generated in situ from copper salts, phosphine ligands and silanes. Moderate to good yields and high diastereoselectivities were obtained in 15 min to 3 h using bis[（2-diphenyl- phosphino）phenyl] ether as the ligand.展开更多
Direct asymmetric aldol additions of acetone/and butanone to a-ketoesters were achieved using L-proline as a chiral catalyst. Various optically active a-hydroxyesters were obtained in the yields of 43%-93% with enanti...Direct asymmetric aldol additions of acetone/and butanone to a-ketoesters were achieved using L-proline as a chiral catalyst. Various optically active a-hydroxyesters were obtained in the yields of 43%-93% with enantioselectivities up. to 81% e.e. The steric effect seems to be an important factor which influences the activity and the selectivity of the reaction. Acetone showed higher reactivity than butanone while the latter provided better enantioselectivity in some cases.展开更多
文摘Copper hydride-catalyzed conjugate reduction-intermolecular aldol addition domino reactions were realized using α,β-unsaturated carboxylates as hydride acceptors and a silane as the reducing reagent. High diastereoselec- tivities were achieved with 4,5-bis（diphenylphosphino）-9,9-dimethylxanthene as the ligand and tert-butyl acrylate as the hydride acceptor.
基金We are grateful to the National Natural Science Foundation of China for financial support （No. 20972020）.
文摘Intramolecular conjugate reduction-aldol addition reactions of β＇-oxoalkyl a,fl-unsaturated carboxylates were performed in the presence of copper catalysts generated in situ from copper salts, phosphine ligands and silanes. Moderate to good yields and high diastereoselectivities were obtained in 15 min to 3 h using bis[（2-diphenyl- phosphino）phenyl] ether as the ligand.
文摘Direct asymmetric aldol additions of acetone/and butanone to a-ketoesters were achieved using L-proline as a chiral catalyst. Various optically active a-hydroxyesters were obtained in the yields of 43%-93% with enantioselectivities up. to 81% e.e. The steric effect seems to be an important factor which influences the activity and the selectivity of the reaction. Acetone showed higher reactivity than butanone while the latter provided better enantioselectivity in some cases.
