The diastereo-and enantioselective tandem cycloisomerization/[4+2]-cycloaddition reaction of cyclopropyl tethered allenyl ketones withα,β-unsaturated carbonyl compounds was realized firstly under mild reaction condi...The diastereo-and enantioselective tandem cycloisomerization/[4+2]-cycloaddition reaction of cyclopropyl tethered allenyl ketones withα,β-unsaturated carbonyl compounds was realized firstly under mild reaction conditions by using bimetallic silver(I)/chiral metal-N,N′-dioxide catalysts,providing a facile and atom-economic route to enantioenriched polysubstituted furopyran derivatives with good results.Possible transition state models were proposed to explain the stereoinduction.展开更多
A highly chemo-and enantioselective alkylation of vinyl azides with 3-bromo-3-substituted oxindoles was achieved through a chiral N,N′-dioxide/Ni(OTf)2-mediated conjugate addition/water addition/elimination tandem pr...A highly chemo-and enantioselective alkylation of vinyl azides with 3-bromo-3-substituted oxindoles was achieved through a chiral N,N′-dioxide/Ni(OTf)2-mediated conjugate addition/water addition/elimination tandem process. Water was critical to the chemo-and enantioselectivity. The hydrated Na3PO4 acted as both a base and a reservoir to regulate the amount of water in solution. A wide range of enantioenriched oxindoles having α-carbonyl-substituted all-carbon quaternary stereocenters were achieved in good yields and good ee values(51 examples, up to 90% yield, 97% ee). Easy transformations of products to analogues of(+)-physovenine and(+)-desoxyeseroline enhanced the synthetic value. Mechanistic studies including control experiments, kinetic studies, and density functional theory(DFT) calculations, enabled a proposition of a possible catalytic cycle along with transition states to elucidate the reaction process and chiral induction.展开更多
Asymmetric nucleophilic addition of 3-substituted NBoc oxindoles to 3-bromooxindoles was designed to directly construct hetero-3,3′-bisoxindoles,with varying vicinal quaternary carbon stereocenters and N-substituents...Asymmetric nucleophilic addition of 3-substituted NBoc oxindoles to 3-bromooxindoles was designed to directly construct hetero-3,3′-bisoxindoles,with varying vicinal quaternary carbon stereocenters and N-substituents.The reaction progressed efficiently with high yields,good diastereo-and enantioselectivity(up to>99%ee)under mild reaction conditions catalyzed by chiral N,N′-dioxide/metal complexes.This methodology enabled the facile transformation of the generated hetero-3,3’-bisoxindoles into diverse hexahydropyrroloindole alkaloids with potential antiparasitic and anticancer properties.展开更多
基金supported by the National Natural Science Foundation of China(21890723,22171189)the Fundamental Research Funds for the Central Universities(YJ201819)。
文摘The diastereo-and enantioselective tandem cycloisomerization/[4+2]-cycloaddition reaction of cyclopropyl tethered allenyl ketones withα,β-unsaturated carbonyl compounds was realized firstly under mild reaction conditions by using bimetallic silver(I)/chiral metal-N,N′-dioxide catalysts,providing a facile and atom-economic route to enantioenriched polysubstituted furopyran derivatives with good results.Possible transition state models were proposed to explain the stereoinduction.
基金supported by the National Natural Science Foundation of China(21871188,21921002)the Sichuan Science and Technology Program(2021YJ0561)the Sichuan University(2020SCUNL204)。
文摘A highly chemo-and enantioselective alkylation of vinyl azides with 3-bromo-3-substituted oxindoles was achieved through a chiral N,N′-dioxide/Ni(OTf)2-mediated conjugate addition/water addition/elimination tandem process. Water was critical to the chemo-and enantioselectivity. The hydrated Na3PO4 acted as both a base and a reservoir to regulate the amount of water in solution. A wide range of enantioenriched oxindoles having α-carbonyl-substituted all-carbon quaternary stereocenters were achieved in good yields and good ee values(51 examples, up to 90% yield, 97% ee). Easy transformations of products to analogues of(+)-physovenine and(+)-desoxyeseroline enhanced the synthetic value. Mechanistic studies including control experiments, kinetic studies, and density functional theory(DFT) calculations, enabled a proposition of a possible catalytic cycle along with transition states to elucidate the reaction process and chiral induction.
基金support from the National Natural Science Foundation of China(grant nos.21625205 and U19A2014).
文摘Asymmetric nucleophilic addition of 3-substituted NBoc oxindoles to 3-bromooxindoles was designed to directly construct hetero-3,3′-bisoxindoles,with varying vicinal quaternary carbon stereocenters and N-substituents.The reaction progressed efficiently with high yields,good diastereo-and enantioselectivity(up to>99%ee)under mild reaction conditions catalyzed by chiral N,N′-dioxide/metal complexes.This methodology enabled the facile transformation of the generated hetero-3,3’-bisoxindoles into diverse hexahydropyrroloindole alkaloids with potential antiparasitic and anticancer properties.
