Dehydrogenation of 9-hydroxy decalinic enones and analogs with DDQ resulted in a formal dienone-phenol type rearrangement via B-ring cleavage, while the corresponding dienone acetates underwent base-catalyzed formal d...Dehydrogenation of 9-hydroxy decalinic enones and analogs with DDQ resulted in a formal dienone-phenol type rearrangement via B-ring cleavage, while the corresponding dienone acetates underwent base-catalyzed formal dienone-phenol type rearrangement analogously.展开更多
Main observation and conclusion A new strategy for the generation of the active Pd-alkyl species from aminal via C-N bond activation has been established,in which the formation of zwitterionic intermediate through aza...Main observation and conclusion A new strategy for the generation of the active Pd-alkyl species from aminal via C-N bond activation has been established,in which the formation of zwitterionic intermediate through aza-Michael addition of aminal to nitrodienes or dienones is identified as a key step for the activation of the C-N bond.The efficient strategy has enabled a new palladium-catalyzed a-aminomethylation of nitro-dienes and dienones via double C-N bond activation.The scope and versatility of the reaction were demonstrated and a broad range of substrates bearing electron-donating and-withdrawing groups on the aromatic rings were all compatible with this reaction to furnish the desired a-aminomethylated products in moderate to good yields with excellent regioselectivities and E/Z selectivities.展开更多
The synthesis of cycloheptanoid-based fused polycyclic frameworks is a challenge for organic chemists due to unfavorable entropic factors and ring strains.Herein,a concise synthesis of 4-desmethyl-rippertenol and 7-ep...The synthesis of cycloheptanoid-based fused polycyclic frameworks is a challenge for organic chemists due to unfavorable entropic factors and ring strains.Herein,a concise synthesis of 4-desmethyl-rippertenol and 7-epi-rippertenol bearing a unique,[6,6,5,7]-fused tetracyclic framework is reported.The route features a novel photoinduced intramolecular cyclization ofα-cyclopropyl dienone followed by an unexpected thermal 1,5-hydrogen migration.展开更多
The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like die...The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like dienones. Six pyridinium ionic liquids were evaluated in allylic oxidation of α-ionone and β-ionone. The 60%-70% yields of 3-oxo-α-ionone were obtained with 0.02 0.20 mmol of CuCl2·2H2O as catalyst, 3-5 mmol of tert-butyl hydroperoxide as oxidant and 1 g of [Bpy]PF6 as solvent for 4-20 h at 60℃. The facile recovery and recycle of catalyst were also achieved. More significantly, peculiar phase behaviors of [Bpy]PF6 and [Epy]PF6 offered the catalytic system advantages of homogeneous reaction and heterogeneous separation. Scanning electron microscope （SEM） images of [Bpy]PF6 provided evidences for the behaviors. Transmission electron microscope （TEM） micrographs showed copper salt nanoparticles catalyst formed and stabilized in pyridinium ionic liquids.展开更多
The construction of polycyclic scaffolds is a sophisticated area of chemical synthesis,however,the direct synthesis of readily accessible chiral 4H-pyran-containing polycyclic compounds remains challenging,likely due ...The construction of polycyclic scaffolds is a sophisticated area of chemical synthesis,however,the direct synthesis of readily accessible chiral 4H-pyran-containing polycyclic compounds remains challenging,likely due to the lack of rational substrate design,appropriate reaction selection,and highly effective catalytic systems.Herein,we present the design and development of a novel organocatalytic cascade reaction for constructing structurally complex chiral polycyclic 4H-pyran scaffolds,featuring adjacent quaternary and tertiary stereocenters,in high yields and excellent stereoselectivities,promoted by a bifunctional phosphonium salt catalyst(up to 95% yield and 98%ee,all>20:1 dr).Additionally,experimental studies and density functional theory(DFT)calculations revealed an intricate cascade process involving Michael addition,nucleophilic addition,isomerization,oxa-nucleophilic attack,and protonation sequences.Hydrogen bonding and CH-πinteractions collaboratively enhance the high enantioselectivities in this innovative cascade protocol.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.20072012 and 20272021)the Foundation for University Key Teacher by the Ministry of Education of China.
文摘Dehydrogenation of 9-hydroxy decalinic enones and analogs with DDQ resulted in a formal dienone-phenol type rearrangement via B-ring cleavage, while the corresponding dienone acetates underwent base-catalyzed formal dienone-phenol type rearrangement analogously.
基金the National Natural Science Foundation of China(Nos.21672199,21790333,21925111 and 21702197)the Fundamental Research Funds for the Central Universities(No.WK2060190086).
文摘Main observation and conclusion A new strategy for the generation of the active Pd-alkyl species from aminal via C-N bond activation has been established,in which the formation of zwitterionic intermediate through aza-Michael addition of aminal to nitrodienes or dienones is identified as a key step for the activation of the C-N bond.The efficient strategy has enabled a new palladium-catalyzed a-aminomethylation of nitro-dienes and dienones via double C-N bond activation.The scope and versatility of the reaction were demonstrated and a broad range of substrates bearing electron-donating and-withdrawing groups on the aromatic rings were all compatible with this reaction to furnish the desired a-aminomethylated products in moderate to good yields with excellent regioselectivities and E/Z selectivities.
基金supported by the National Key Research and Development Program of China(grant no.2018YFC0310905)the National Science Foundation of China(grant nos.21632002,21871012,and 21801123)the Shenzhen Basic Research Program(grant nos.JCYJ20180302180215524 and JCYJ20170818091450164).
文摘The synthesis of cycloheptanoid-based fused polycyclic frameworks is a challenge for organic chemists due to unfavorable entropic factors and ring strains.Herein,a concise synthesis of 4-desmethyl-rippertenol and 7-epi-rippertenol bearing a unique,[6,6,5,7]-fused tetracyclic framework is reported.The route features a novel photoinduced intramolecular cyclization ofα-cyclopropyl dienone followed by an unexpected thermal 1,5-hydrogen migration.
基金Supported by the National Natural Science Foundation of China （20472057）
文摘The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like dienones. Six pyridinium ionic liquids were evaluated in allylic oxidation of α-ionone and β-ionone. The 60%-70% yields of 3-oxo-α-ionone were obtained with 0.02 0.20 mmol of CuCl2·2H2O as catalyst, 3-5 mmol of tert-butyl hydroperoxide as oxidant and 1 g of [Bpy]PF6 as solvent for 4-20 h at 60℃. The facile recovery and recycle of catalyst were also achieved. More significantly, peculiar phase behaviors of [Bpy]PF6 and [Epy]PF6 offered the catalytic system advantages of homogeneous reaction and heterogeneous separation. Scanning electron microscope （SEM） images of [Bpy]PF6 provided evidences for the behaviors. Transmission electron microscope （TEM） micrographs showed copper salt nanoparticles catalyst formed and stabilized in pyridinium ionic liquids.
基金supported by the National Natural Science Foundation of China(22222109,21921002,22101189,22371190)the National Key R&D Program of China(2018YFA0903500)+5 种基金the Beijing National Laboratory for Molecular Sciences(BNLMS202101)the Sichuan Science Foundation for Distinguished Young Scholars(2023NSFSC1921)the Sichuan Provincial Natural Science Foundation(2022NSFSC1181,24NSFSC6590)the Fundamental Research Funds from Sichuan University(2020SCUNL108)the Fundamental Research Funds for the Central Universitiesthe College of Chemistry and the Analytical&Testing Center of Sichuan University for the support。
文摘The construction of polycyclic scaffolds is a sophisticated area of chemical synthesis,however,the direct synthesis of readily accessible chiral 4H-pyran-containing polycyclic compounds remains challenging,likely due to the lack of rational substrate design,appropriate reaction selection,and highly effective catalytic systems.Herein,we present the design and development of a novel organocatalytic cascade reaction for constructing structurally complex chiral polycyclic 4H-pyran scaffolds,featuring adjacent quaternary and tertiary stereocenters,in high yields and excellent stereoselectivities,promoted by a bifunctional phosphonium salt catalyst(up to 95% yield and 98%ee,all>20:1 dr).Additionally,experimental studies and density functional theory(DFT)calculations revealed an intricate cascade process involving Michael addition,nucleophilic addition,isomerization,oxa-nucleophilic attack,and protonation sequences.Hydrogen bonding and CH-πinteractions collaboratively enhance the high enantioselectivities in this innovative cascade protocol.
