Palladium‐catalyzed asymmetric allylic alkylation(AAA)of vinyl benzoxazinanones has become an important strategy for the synthesis of chiral nitrogen‐containing heterocycle compounds.However,the asymmetric synthesis...Palladium‐catalyzed asymmetric allylic alkylation(AAA)of vinyl benzoxazinanones has become an important strategy for the synthesis of chiral nitrogen‐containing heterocycle compounds.However,the asymmetric synthesis of linear‐selective products has rarely been reported.The simultaneous control of regio‐,E/Z‐and enantioselectivities constitutes a major challenge and inhibits the advancement of this chemistry.Herein,we present a palladium‐catalyzed AAA of vinyl benzoxazinanones withα‐thiocyanato ketones,affording various chiral thiocyanates characterized with high linear‐,E‐and stereoselectivities.The reaction has a broad substrate scope and the chiral thiocyanates can be transformed to useful heterocycles.Experimental and computational studies suggest an inner‐sphere mechanism for AAA process,which results from the acidic and coordination effect of the nucleophilic substrates with palladium catalyst.展开更多
The cooperative catalysis of an achiral Lewis base and a chiral N-heterocyclic carbene(NHC)enables a highly enantioselective[4+3]annulation of benzoxazinanones with isatin-derived enals.DMAP serves as a nucleophilic L...The cooperative catalysis of an achiral Lewis base and a chiral N-heterocyclic carbene(NHC)enables a highly enantioselective[4+3]annulation of benzoxazinanones with isatin-derived enals.DMAP serves as a nucleophilic Lewis base to promote decarboxylation of benzoxazinanones,which leads to azaortho-xylylene intermediates that undergo[4+3]annulations with NHC-bound homoenolates.This method breaks the substrate scope limitation of transition-metal-catalyzed variants,thus a broader range of benzoxazinanones are tolerated,and provides a straightforward entry to enantioenriched spirooxindoles in high structural diversity.展开更多
A Pd-catalyzed asymmetric decarboxylative[4+2]cycloaddition of 3-nitroindoles and vinyl benzoxazinanones is developed through a dearomatization approach.The reaction provides an efficient protocol for constructing a s...A Pd-catalyzed asymmetric decarboxylative[4+2]cycloaddition of 3-nitroindoles and vinyl benzoxazinanones is developed through a dearomatization approach.The reaction provides an efficient protocol for constructing a series of chiral tetrahydro-5H-indolo[2,3-b]quinolines in high yields and with excellent diastereo-and enantioselectivities.展开更多
A Pd-catalyzed enantioselective synthesis of 2-methyl-3-methyleneindoline in up to 89% yield and 84% ee from racemic vinyl benzoxazinanones has been developed with the help of(R,R)-BenzP*ligand.Mechanism studies suppo...A Pd-catalyzed enantioselective synthesis of 2-methyl-3-methyleneindoline in up to 89% yield and 84% ee from racemic vinyl benzoxazinanones has been developed with the help of(R,R)-BenzP*ligand.Mechanism studies support the formation of palladacyclobutane as the key intermediate via C2 attack to π-allyl Pd complex.The β-hydride elimination provides a new reaction pathway for the palladacyclobutane.展开更多
文摘Palladium‐catalyzed asymmetric allylic alkylation(AAA)of vinyl benzoxazinanones has become an important strategy for the synthesis of chiral nitrogen‐containing heterocycle compounds.However,the asymmetric synthesis of linear‐selective products has rarely been reported.The simultaneous control of regio‐,E/Z‐and enantioselectivities constitutes a major challenge and inhibits the advancement of this chemistry.Herein,we present a palladium‐catalyzed AAA of vinyl benzoxazinanones withα‐thiocyanato ketones,affording various chiral thiocyanates characterized with high linear‐,E‐and stereoselectivities.The reaction has a broad substrate scope and the chiral thiocyanates can be transformed to useful heterocycles.Experimental and computational studies suggest an inner‐sphere mechanism for AAA process,which results from the acidic and coordination effect of the nucleophilic substrates with palladium catalyst.
基金the National Natural Science Foundation of China(grant nos.21831007 and 22071229).
文摘The cooperative catalysis of an achiral Lewis base and a chiral N-heterocyclic carbene(NHC)enables a highly enantioselective[4+3]annulation of benzoxazinanones with isatin-derived enals.DMAP serves as a nucleophilic Lewis base to promote decarboxylation of benzoxazinanones,which leads to azaortho-xylylene intermediates that undergo[4+3]annulations with NHC-bound homoenolates.This method breaks the substrate scope limitation of transition-metal-catalyzed variants,thus a broader range of benzoxazinanones are tolerated,and provides a straightforward entry to enantioenriched spirooxindoles in high structural diversity.
基金financial support from the National Natural Science Foundation of China (NSFC, Nos. 21772215, 21532010 and 21472214)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB20030100)+2 种基金the Chinese Academy of Sciencesthe Technology Commission of Shanghai Municipalitythe Croucher Foundation of Hong Kong
文摘A Pd-catalyzed asymmetric decarboxylative[4+2]cycloaddition of 3-nitroindoles and vinyl benzoxazinanones is developed through a dearomatization approach.The reaction provides an efficient protocol for constructing a series of chiral tetrahydro-5H-indolo[2,3-b]quinolines in high yields and with excellent diastereo-and enantioselectivities.
基金supported by National Natural Science Foundation of China(NSFC,No.21602130)Shanghai Jiao Tong University。
文摘A Pd-catalyzed enantioselective synthesis of 2-methyl-3-methyleneindoline in up to 89% yield and 84% ee from racemic vinyl benzoxazinanones has been developed with the help of(R,R)-BenzP*ligand.Mechanism studies support the formation of palladacyclobutane as the key intermediate via C2 attack to π-allyl Pd complex.The β-hydride elimination provides a new reaction pathway for the palladacyclobutane.