Several isoxazoline compounds were obtained by the 1,3-dipolar cycloaddition of benzonitrile oxide to 5-(R)-(l-menthyloxy)-2(5H)-furanone. The reaction condition was investigated preliminarily, the structures of thes...Several isoxazoline compounds were obtained by the 1,3-dipolar cycloaddition of benzonitrile oxide to 5-(R)-(l-menthyloxy)-2(5H)-furanone. The reaction condition was investigated preliminarily, the structures of these compounds have been established via the analysis of NMR data(involved NOEID or HMBC) and the reaction seems occurred regioselectively.展开更多
A new highly efficient and reusable Cu-MOF has been developed for the regioselective synthesis of 1,2,3-triazoles via the 1,3-dipolar cycloaddition of organic azides to terminal alkynes under solvent-free conditions.T...A new highly efficient and reusable Cu-MOF has been developed for the regioselective synthesis of 1,2,3-triazoles via the 1,3-dipolar cycloaddition of organic azides to terminal alkynes under solvent-free conditions.This protocol has the advantages of excellent product yields and a low catalyst loading.Moreover,the catalyst may be recovered and reused efficiently up to 5 cycles without major loss of reactivity.展开更多
The development of novel synthons and efficient methods to synthesize chiral polycyclic indoles has been a hot topic in organic synthesis and medicinal chemistry owing to their broad applications in medicines,pesticid...The development of novel synthons and efficient methods to synthesize chiral polycyclic indoles has been a hot topic in organic synthesis and medicinal chemistry owing to their broad applications in medicines,pesticides,and other functional molecules.Here,we disclosed novel indolyl substituted metal-allyl zwitterionic intermediates through the decarboxylation of conveniently available vinyl indoloxazolidones,which could be regarded as two types of dipolar species through the anionic delocalization.The palladium-π-allyl species tended to serve as an all-carbon 1,3-dipole in the asymmetric[3+2]cycloaddition with electrondeficient alkenes,which furnished polysubstituted cyclopenta[b]indoles with high regio-and stereoselectivities.Meanwhile,the iridium-π-allyl species was recognized as an aza-1,3-dipole in asymmetric[3+2]cycloaddition with in situ generated C1 ammonium enolates,affording pyrrolo[1,2-α]indoles with high diastereo-and enantioselectivities.In addition,the dipolar cycloadditions could be easily scaled-up and several synthetic transformations of the cycloadducts were demonstrated for the rapid synthesis of diverse chiral polycyclic indoles.展开更多
The dipolar cycloaddition reaction of allenyl perfluoroalkyl sulfones （1） to nitrones （2） was described. Unlike nonfluorine-containing allenyl sulfones, 1 reacted readily with 2 in ether at room temperatttre and u...The dipolar cycloaddition reaction of allenyl perfluoroalkyl sulfones （1） to nitrones （2） was described. Unlike nonfluorine-containing allenyl sulfones, 1 reacted readily with 2 in ether at room temperatttre and unusual zwitterionic cycloadducts （3） were obtained in good yields due to the strong electron-withdrawing effect of perfluoroalkyl groups. The structure of 3 was characterized by spectral analyses and X-ray crystallography.展开更多
The azabicyclo[3.3.0]octane scaffold represents a privileged structural motif in medicinal chemistry,yet its synthesis typically requires laborious multistep sequences.Herein,we disclose a palladium-photoredox relay c...The azabicyclo[3.3.0]octane scaffold represents a privileged structural motif in medicinal chemistry,yet its synthesis typically requires laborious multistep sequences.Herein,we disclose a palladium-photoredox relay catalytic strategy that combines dipolar[4+4]cycloaddition with transannular cascade processes.This domino protocol enables single-step construction of three distinct bioisosteric frameworks(aza-,oxaza-,and diazabicyclo[3.3.0]octanes)from linear precursors,achieving yields up to 94%with broad functional group tolerance.Gram-scale synthesis and diverse downstream transformations underscore the practical utility of this methodology.展开更多
The 1,3-dipolar cycloaddition reaction of cis-[Co(N_(3))_(2)(en)_(2)]NO_(3)1 with different organonitriles(NCR)under focussed microwave irradiation produced bis-tetrazolate complexes[Co(N_(4)CR)_(2)(en)_(2)](NO_(3)).I...The 1,3-dipolar cycloaddition reaction of cis-[Co(N_(3))_(2)(en)_(2)]NO_(3)1 with different organonitriles(NCR)under focussed microwave irradiation produced bis-tetrazolate complexes[Co(N_(4)CR)_(2)(en)_(2)](NO_(3)).Interestingly,in the case of 3-cyano pyridine the reaction produced both cis-and trans-isomers(cis-2 and trans-2),whereas for 4-cyano pyridine the compound obtained was exclusively cis(cis-3)and for 4-bromobenzonitrile it was only the trans-(trans-4)compound which was isolated.This indicates a probable role of remote substitution of the phenyl ring in dictating the formation of the preferential isomer.When starting from the trans-isomer of the diazido complex(trans-[Co(N_(3))_(2)(en)_(2)]ClO_(4),1a),upon reacting with different nitriles a mixture of cis-and trans-isomers of[Co(N_(4)CR)_(2)(en)_(2)]ClO_(4)was produced in each case,with a greater preference towards cis-geometry[R=4-NC_(5)H_(4)(cis-5 and trans-5),4-BrC_(6)H_(4)(cis-6 and trans-6)and C_(6)H_(5)(cis-7 and trans-7)].The preferential formation of the cis-analogue of compound trans-4 when starting from the trans-precursor was quite curious.A theoretical investigation of compounds trans-4 and cis-6 reveals that the greater stability of the trans-complex 4 may arise from additional van der Waals interactions in the solid state because of the presence of an extra DMF molecule as solvent of crystallization.However,an interacting counter-anion and a probable halogen–halogen interaction may also contribute to the formation of preferential isomers for cycloaddition complexes,even in the solution state.展开更多
文摘Several isoxazoline compounds were obtained by the 1,3-dipolar cycloaddition of benzonitrile oxide to 5-(R)-(l-menthyloxy)-2(5H)-furanone. The reaction condition was investigated preliminarily, the structures of these compounds have been established via the analysis of NMR data(involved NOEID or HMBC) and the reaction seems occurred regioselectively.
基金financial support for this research from the Welch Foundation(grant no.AX-1593)the NIHNIGMS(grant no.SC1GM082718)the financial support for this research from the Welch Foundation(grant no.AX-1730).
文摘A new highly efficient and reusable Cu-MOF has been developed for the regioselective synthesis of 1,2,3-triazoles via the 1,3-dipolar cycloaddition of organic azides to terminal alkynes under solvent-free conditions.This protocol has the advantages of excellent product yields and a low catalyst loading.Moreover,the catalyst may be recovered and reused efficiently up to 5 cycles without major loss of reactivity.
基金the National Natural Science Foundation of China(21901072)the China Postdoctoral Science Foundation(2019T120310)Shanghai Sailing Program(18YF140560)。
文摘The development of novel synthons and efficient methods to synthesize chiral polycyclic indoles has been a hot topic in organic synthesis and medicinal chemistry owing to their broad applications in medicines,pesticides,and other functional molecules.Here,we disclosed novel indolyl substituted metal-allyl zwitterionic intermediates through the decarboxylation of conveniently available vinyl indoloxazolidones,which could be regarded as two types of dipolar species through the anionic delocalization.The palladium-π-allyl species tended to serve as an all-carbon 1,3-dipole in the asymmetric[3+2]cycloaddition with electrondeficient alkenes,which furnished polysubstituted cyclopenta[b]indoles with high regio-and stereoselectivities.Meanwhile,the iridium-π-allyl species was recognized as an aza-1,3-dipole in asymmetric[3+2]cycloaddition with in situ generated C1 ammonium enolates,affording pyrrolo[1,2-α]indoles with high diastereo-and enantioselectivities.In addition,the dipolar cycloadditions could be easily scaled-up and several synthetic transformations of the cycloadducts were demonstrated for the rapid synthesis of diverse chiral polycyclic indoles.
文摘The dipolar cycloaddition reaction of allenyl perfluoroalkyl sulfones （1） to nitrones （2） was described. Unlike nonfluorine-containing allenyl sulfones, 1 reacted readily with 2 in ether at room temperatttre and unusual zwitterionic cycloadducts （3） were obtained in good yields due to the strong electron-withdrawing effect of perfluoroalkyl groups. The structure of 3 was characterized by spectral analyses and X-ray crystallography.
基金supported by the National Natural Science Foundation of China(22371259,22171082,22201253)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2022R01007)the Start-up Research Grant from Zhejiang Normal University。
文摘The azabicyclo[3.3.0]octane scaffold represents a privileged structural motif in medicinal chemistry,yet its synthesis typically requires laborious multistep sequences.Herein,we disclose a palladium-photoredox relay catalytic strategy that combines dipolar[4+4]cycloaddition with transannular cascade processes.This domino protocol enables single-step construction of three distinct bioisosteric frameworks(aza-,oxaza-,and diazabicyclo[3.3.0]octanes)from linear precursors,achieving yields up to 94%with broad functional group tolerance.Gram-scale synthesis and diverse downstream transformations underscore the practical utility of this methodology.
文摘The 1,3-dipolar cycloaddition reaction of cis-[Co(N_(3))_(2)(en)_(2)]NO_(3)1 with different organonitriles(NCR)under focussed microwave irradiation produced bis-tetrazolate complexes[Co(N_(4)CR)_(2)(en)_(2)](NO_(3)).Interestingly,in the case of 3-cyano pyridine the reaction produced both cis-and trans-isomers(cis-2 and trans-2),whereas for 4-cyano pyridine the compound obtained was exclusively cis(cis-3)and for 4-bromobenzonitrile it was only the trans-(trans-4)compound which was isolated.This indicates a probable role of remote substitution of the phenyl ring in dictating the formation of the preferential isomer.When starting from the trans-isomer of the diazido complex(trans-[Co(N_(3))_(2)(en)_(2)]ClO_(4),1a),upon reacting with different nitriles a mixture of cis-and trans-isomers of[Co(N_(4)CR)_(2)(en)_(2)]ClO_(4)was produced in each case,with a greater preference towards cis-geometry[R=4-NC_(5)H_(4)(cis-5 and trans-5),4-BrC_(6)H_(4)(cis-6 and trans-6)and C_(6)H_(5)(cis-7 and trans-7)].The preferential formation of the cis-analogue of compound trans-4 when starting from the trans-precursor was quite curious.A theoretical investigation of compounds trans-4 and cis-6 reveals that the greater stability of the trans-complex 4 may arise from additional van der Waals interactions in the solid state because of the presence of an extra DMF molecule as solvent of crystallization.However,an interacting counter-anion and a probable halogen–halogen interaction may also contribute to the formation of preferential isomers for cycloaddition complexes,even in the solution state.
