Reaction of Cp2TiCl2-Mg synthetic equivalent of practical Ti(II) reagent with propargyl alcohol derivatives affords allenyl titanium compounds in good yields.thus, providing an efficient and practical methods for synt...Reaction of Cp2TiCl2-Mg synthetic equivalent of practical Ti(II) reagent with propargyl alcohol derivatives affords allenyl titanium compounds in good yields.thus, providing an efficient and practical methods for synthesis of both allenyl and homopropargyl alcohols by the successive treatment with aldehydes and ketones.展开更多
Furans bearing alkynyl substituents are highly useful in organic synthesis.However,the methodologies to access these important furan derivatives are rather limited.We herein report an efficient synthesis of alkynylate...Furans bearing alkynyl substituents are highly useful in organic synthesis.However,the methodologies to access these important furan derivatives are rather limited.We herein report an efficient synthesis of alkynylated furan derivatives based on Pd-catalyzed oxidative cross-coupling reaction between allenyl ketones and terminal alkynes.This novel synthesis of alkynylated furans with wide substrate scope is operationally simple and tolerates various functional groups.Mechanistically,the formation of the palladium carbene through cycloisomerization and the subsequent alkynyl migratory insertion are proposed as the key steps in the transformation.The reaction reported in this paper further demonstrates the generality of the carbene-based cross coupling.展开更多
Allenylboronates represent a very intriguing class of organoborons but are challenging to synthesis.In addition,these compounds are typically unstable,rendering the separation difficult.We report herein a practical an...Allenylboronates represent a very intriguing class of organoborons but are challenging to synthesis.In addition,these compounds are typically unstable,rendering the separation difficult.We report herein a practical and concise route to a new class of stable,easy-separable allenyl B(MIDA)via a hydrazination/fragmentation of B(MIDA)-propargylic alcohols.The synthesis of optically active allenyl B(MIDA)was also achieved.Interesting reactivity of the resulting product was observed.展开更多
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
Allenes and oxindoles are two classes of very important compounds for medicinal chemistry and organic chemistry.Thus,it is of high interest to combine an allene and an oxindole into one molecule.Herein,the first examp...Allenes and oxindoles are two classes of very important compounds for medicinal chemistry and organic chemistry.Thus,it is of high interest to combine an allene and an oxindole into one molecule.Herein,the first example of palladium-catalyzed exclusive 2,3-allenylation reaction of oxindoles with 2,3-allenylic carbonates has been successfully developed.A rationale for the selectivity of 2,3-allenylation over the expected 1,3-alkadienylation has been proposed.展开更多
Preparation of allenyl perfluoroalkyl sulfones from perfluoroalkyl sulfinyl chlorides and their reactions with secondary amines and water were studied. At room temperature secondary amines reacted readily with allenyl...Preparation of allenyl perfluoroalkyl sulfones from perfluoroalkyl sulfinyl chlorides and their reactions with secondary amines and water were studied. At room temperature secondary amines reacted readily with allenyl perfluoroalkyl sulfones to give the corresponding enamine adducts, which underwent rearrangement to afford conjugate enamines in refluxing toluene. Good diastereoslectivities were observed in the addition of diethylamine to 7-ethyl-7-methylallenyl perfluoroalkyl sulfones. In refluxing acetonitrile, water could also undergo the similar addition with allenyl perfluoroalkyl sulfones.展开更多
Hydroselenation of 1, 2-allenyl sulfoxides give 2-organoseleno substituted allyl sulfoxides in high yields and the reaction is absolute regioselective.
The hydrohalogenation reaction of 1-alkyl substituted 1,2-allenyl carboxylic acid esters (1) with MX (M= Na, or Li, X= Cl, Br, I) afforded a mixture of β,γ-unsaturated 3-halo–3-alkenoates (2) and Q,P unsaturated 3-...The hydrohalogenation reaction of 1-alkyl substituted 1,2-allenyl carboxylic acid esters (1) with MX (M= Na, or Li, X= Cl, Br, I) afforded a mixture of β,γ-unsaturated 3-halo–3-alkenoates (2) and Q,P unsaturated 3-halo-2-alkenoates (3) in HOAc, while using a mixture of HOAC-CF3CO2H (1:1) or CF3C2H as the reaction medium the corresponding reaction cleanly produced β,γ -unsaturated 3-hale3-alkenoates (2) as the sole products in high yields. The subsequent coupling reactions were studied.展开更多
文摘Reaction of Cp2TiCl2-Mg synthetic equivalent of practical Ti(II) reagent with propargyl alcohol derivatives affords allenyl titanium compounds in good yields.thus, providing an efficient and practical methods for synthesis of both allenyl and homopropargyl alcohols by the successive treatment with aldehydes and ketones.
基金supported by NSFC(22371008),BNLMSLaboratory for Synthetic Chemistry and Chemical Biology of Health@InnoHK of ITC,HKSAR.
文摘Furans bearing alkynyl substituents are highly useful in organic synthesis.However,the methodologies to access these important furan derivatives are rather limited.We herein report an efficient synthesis of alkynylated furan derivatives based on Pd-catalyzed oxidative cross-coupling reaction between allenyl ketones and terminal alkynes.This novel synthesis of alkynylated furans with wide substrate scope is operationally simple and tolerates various functional groups.Mechanistically,the formation of the palladium carbene through cycloisomerization and the subsequent alkynyl migratory insertion are proposed as the key steps in the transformation.The reaction reported in this paper further demonstrates the generality of the carbene-based cross coupling.
基金supported by the National Natural Science Foundation of China(Nos.22022114 and 21971261)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515010624)+1 种基金the Fundamental Research Funds for the Central Universities(No.20ykzd12)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Y093)。
文摘Allenylboronates represent a very intriguing class of organoborons but are challenging to synthesis.In addition,these compounds are typically unstable,rendering the separation difficult.We report herein a practical and concise route to a new class of stable,easy-separable allenyl B(MIDA)via a hydrazination/fragmentation of B(MIDA)-propargylic alcohols.The synthesis of optically active allenyl B(MIDA)was also achieved.Interesting reactivity of the resulting product was observed.
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Financial support from the National Natural Science Founda tion Founda tion of China(Grant Nos.21690063 and 21988101)is greatly appreciated.We thank Mr.Yifan Cui in this group for reproducing the results of 3ba presented in Table 3.
文摘Allenes and oxindoles are two classes of very important compounds for medicinal chemistry and organic chemistry.Thus,it is of high interest to combine an allene and an oxindole into one molecule.Herein,the first example of palladium-catalyzed exclusive 2,3-allenylation reaction of oxindoles with 2,3-allenylic carbonates has been successfully developed.A rationale for the selectivity of 2,3-allenylation over the expected 1,3-alkadienylation has been proposed.
基金Project supported by the National Natural Science Foundation of China（No.20572124）.
文摘Preparation of allenyl perfluoroalkyl sulfones from perfluoroalkyl sulfinyl chlorides and their reactions with secondary amines and water were studied. At room temperature secondary amines reacted readily with allenyl perfluoroalkyl sulfones to give the corresponding enamine adducts, which underwent rearrangement to afford conjugate enamines in refluxing toluene. Good diastereoslectivities were observed in the addition of diethylamine to 7-ethyl-7-methylallenyl perfluoroalkyl sulfones. In refluxing acetonitrile, water could also undergo the similar addition with allenyl perfluoroalkyl sulfones.
基金We ale grateful to the National Natural Science Foundation of China(Project No.20272050,20332060)for financial support.
文摘Hydroselenation of 1, 2-allenyl sulfoxides give 2-organoseleno substituted allyl sulfoxides in high yields and the reaction is absolute regioselective.
基金National Natural Science Foundation of China (No. 29525202)Shanghai Municipal Cormnittee of Science and Technology (No. 98QA14001).
文摘The hydrohalogenation reaction of 1-alkyl substituted 1,2-allenyl carboxylic acid esters (1) with MX (M= Na, or Li, X= Cl, Br, I) afforded a mixture of β,γ-unsaturated 3-halo–3-alkenoates (2) and Q,P unsaturated 3-halo-2-alkenoates (3) in HOAc, while using a mixture of HOAC-CF3CO2H (1:1) or CF3C2H as the reaction medium the corresponding reaction cleanly produced β,γ -unsaturated 3-hale3-alkenoates (2) as the sole products in high yields. The subsequent coupling reactions were studied.
