Axially chiral molecules have been widely used in inorganic,material and medicinal chemistry.Compared with well-established N-heterocyclic carbene(NHC)-catalyzed asymmetric construction of centrally chiral molecules,N...Axially chiral molecules have been widely used in inorganic,material and medicinal chemistry.Compared with well-established N-heterocyclic carbene(NHC)-catalyzed asymmetric construction of centrally chiral molecules,NHC-catalyzed atroposelective synthesis of axially chiral molecules remains largely underdeveloped.Notably,alkynyl acyl azolium intermediates were commonly used in constructing a heteroaryl ring to furnish axially enantioenriched heteroaryl-aryls.The inherent character of the intermediates often led to react with sterically hindered substrates difficultly.Herein,we have successfully disclosed the atroposelective synthesis of axially chiral heteroaryl-aryls from sterically hindered enols through the use of chiral NHCs as catalysts for highly enantioselective Coates-Claisen rearrangements via catalytically generatedα,β-unsaturated acyl azoliums.This approach will enable the concise synthesis of valuable tetra-ortho-substituted 2-pyrones in one step with good yield and chirality control.展开更多
Lacebark pine （Pinus bungeana）, an evergreen conifer species native to China, is noted for its graceful profile. It has a height up to 30 m. Bark on young trees smooth, dull grey, scaling off in small patches like a...Lacebark pine （Pinus bungeana）, an evergreen conifer species native to China, is noted for its graceful profile. It has a height up to 30 m. Bark on young trees smooth, dull grey, scaling off in small patches like a plane tree, changing to chalky-white on old trunks, by which the species can be recognized from a long distance.展开更多
With the hypothesis of simple units integration to create new reactivities,a strategy for the synthesis of polyfunctionalized 5-alkenyl-3-carbonylfurans fromγ-hydroxyl enal and 1,3-dicarbonyl compounds is established...With the hypothesis of simple units integration to create new reactivities,a strategy for the synthesis of polyfunctionalized 5-alkenyl-3-carbonylfurans fromγ-hydroxyl enal and 1,3-dicarbonyl compounds is established,featuring readily available starting materials,high efficiency,good functional groups compatibility,green chemistry with high atom economy and only water release,etc.,to provide a series of polyfunctionalized 5-alkenyl-3-carbonylfurans,which could be applied to the late-stage functionalization of naturally occurring compounds and bioactive molecules,as well as the transformation to pyrroles and polycyclic aromatic hydrocarbon via electrocyclic reaction.Theγ-hydroxyl has played an important role in the unexpected process of ring opening isomerization of 2H-pyran to furanones,as confirmed by detailed mechanistic studies.展开更多
A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to （E） selective a, β-unsamrated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to imin...A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to （E） selective a, β-unsamrated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to iminium ions in a catalytic fashion.展开更多
基金supported by the National Key R&D Program of China (2017YFA0204704)the National Natural Science Foundation of China (21602105)+2 种基金the General Program of Chongqing Natural Science(cstc2020jcyj-msxmX0712)Ningbo Natural Science Foundation (202003N4063)the Natural Science Foundation of Jiangsu Province (BK20221309)
文摘Axially chiral molecules have been widely used in inorganic,material and medicinal chemistry.Compared with well-established N-heterocyclic carbene(NHC)-catalyzed asymmetric construction of centrally chiral molecules,NHC-catalyzed atroposelective synthesis of axially chiral molecules remains largely underdeveloped.Notably,alkynyl acyl azolium intermediates were commonly used in constructing a heteroaryl ring to furnish axially enantioenriched heteroaryl-aryls.The inherent character of the intermediates often led to react with sterically hindered substrates difficultly.Herein,we have successfully disclosed the atroposelective synthesis of axially chiral heteroaryl-aryls from sterically hindered enols through the use of chiral NHCs as catalysts for highly enantioselective Coates-Claisen rearrangements via catalytically generatedα,β-unsaturated acyl azoliums.This approach will enable the concise synthesis of valuable tetra-ortho-substituted 2-pyrones in one step with good yield and chirality control.
文摘Lacebark pine （Pinus bungeana）, an evergreen conifer species native to China, is noted for its graceful profile. It has a height up to 30 m. Bark on young trees smooth, dull grey, scaling off in small patches like a plane tree, changing to chalky-white on old trunks, by which the species can be recognized from a long distance.
基金Financial support from National Natural Science Foundation of China(Grant No.22201187)the starting grant from Capital Medical University(Grant No.3100-12400123)。
文摘With the hypothesis of simple units integration to create new reactivities,a strategy for the synthesis of polyfunctionalized 5-alkenyl-3-carbonylfurans fromγ-hydroxyl enal and 1,3-dicarbonyl compounds is established,featuring readily available starting materials,high efficiency,good functional groups compatibility,green chemistry with high atom economy and only water release,etc.,to provide a series of polyfunctionalized 5-alkenyl-3-carbonylfurans,which could be applied to the late-stage functionalization of naturally occurring compounds and bioactive molecules,as well as the transformation to pyrroles and polycyclic aromatic hydrocarbon via electrocyclic reaction.Theγ-hydroxyl has played an important role in the unexpected process of ring opening isomerization of 2H-pyran to furanones,as confirmed by detailed mechanistic studies.
基金the financial support from the National Science Foun-dation (CHE-1057569,W. W.)the China 111 Project (B07023,J. L. and W. W.)+1 种基金the National Natural Science Foundation of China (20972051,X. Y.-H.)the Science and Technology Commission of Shanghai Mu-nicipality (08430703900 & 08431901800,X. Y.-H.)
文摘A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to （E） selective a, β-unsamrated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to iminium ions in a catalytic fashion.
