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Jie Wu - One of the best experts on this subject based on the ideXlab platform.
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an unexpected three component reaction of 2 alkylenecyclobutanone and n 2 alkynylbenzylidene hydrazide with water
RSC Advances, 2015Co-Authors: He Wang, Jie WuAbstract:The generation of 3-(pyrazolo[5,1-a]isoquinolin-1-yl)propanoic acids via a silver(I)-catalyzed three-component reaction of 2-alkylenecyclobutanone and N′-(2-alkynylbenzylidene)hydrazide with water is reported. This unexpected transformation proceeds through 6-Endo Cyclization, [3 + 2] cycloaddition, and rearrangement, leading to 3-(pyrazolo[5,1-a]isoquinolin-1-yl)propanoic acids in good yields.
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synthesis of pyrazolo 5 1 a isoquinolines via silver i rhodium i cooperative catalysis in the reaction of n 2 alkynylbenzylidene hydrazide with cycloprop 2 ene 1 1 dicarboxylate
Organic and Biomolecular Chemistry, 2012Co-Authors: Xingxin Yu, Chen Mo, Jie WuAbstract:A tandem reaction between N′-(2-alkynylbenzylidene)hydrazide and cycloprop-2-ene-1,1-dicarboxylate co-catalyzed by silver triflate and tris(triphenylphosphine)rhodium chloride is reported. The reaction proceeds through 6-Endo-Cyclization, [3 + 2] cycloaddition, cyclopropane opening, and aromatization, leading to pyrazolo[5,1-a]isoquinolines in moderate to good yields.
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an unexpected silver triflate catalyzed tandem reaction of n 2 alkynylbenzylidene hydrazide with ketene
ChemInform, 2012Co-Authors: Shouzhi Pu, Jie WuAbstract:The silver-catalyzed reaction of hydrazides (I) with in situ generated ketenes proceeds via 6-Endo-Cyclization, [3 + 2] cycloaddition, and intramolecular rearrangement to afford 2,6-diaza-bicyclo[3.2.2]non-6-en-3-ones (III).
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an unexpected silver triflate catalyzed tandem reaction of n 2 alkynylbenzylidene hydrazide with ketene
Chemical Communications, 2012Co-Authors: Shouzhi Pu, Jie WuAbstract:An unexpected silver triflate-catalyzed tandem reaction of N′-(2-alkynylbenzylidene)hydrazide with ketene through 6-Endo-Cyclization, [3+2] cycloaddition and rearrangement is reported. This reaction proceeds efficiently to generate the molecular complexity with the formation of four bonds in a one-pot procedure.
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three component reaction of n 2 alkynylbenzylidene hydrazide alkyne with sulfonyl azide via a multicatalytic process a novel and concise approach to 2 amino h pyrazolo 5 1 a isoquinolines
ChemInform, 2011Co-Authors: Shaoyu Li, Jie WuAbstract:The formation of the desired heterocyclic scaffolds proceeds via 6-Endo Cyclization and [3 +3 ] cycloaddition followed by aromatization.
Teck-peng Loh - One of the best experts on this subject based on the ideXlab platform.
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palladium catalyzed cycloaromatization alkylation of o alkynyl styrenes
Journal of Organic Chemistry, 2019Co-Authors: Meng Zhao, Teck-peng Loh, Xiao-wei LiuAbstract:A Pd(II)-catalyzed mild and highly regioselective 6-Endo Cyclization/alkylation reaction of o-(alkynyl)styrenes with simple allylic alcohols has been developed. Under mild reaction conditions, the vinyl palladium species generated in situ after Cyclization could insert a C-C double bond of allylic alcohol through a cross-coupling reaction and led to the formation of (alkyl)naphthalenes. This cascade cross-coupling reaction represents a direct and atom economic method for the construction of functionalized naphthalene derivatives in moderate to good yields.
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Palladium-Catalyzed Cascade Intramolecular Cyclization and Allylation of Enynoates with Allylic Alcohols
2019Co-Authors: Sheng-qi Qiu, Tanveer Ahmad, Teck-peng LohAbstract:A Pd(II)-catalyzed mild and highly regioselective 6-Endo Cyclization/allylation reaction of enynoates with simple allylic alcohols has been developed. Under mild reaction conditions, the vinyl palladium species generated in situ after Cyclization could insert C–C double bond of allylic alcohol through cross-coupling reaction and lead to the formation of allyl pyrone via β-OH elimination. This cascade cross-coupling reaction represents a direct and atom economic methodology for the construction of novel allyl pyrones in moderate to good yields
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Palladium-Catalyzed Dialkylation of C–C Triple Bonds: Access to Multi-Functionalized Indenes
2019Co-Authors: Xiao-wei Liu, Dong-ting Dai, Meng Zhao, Cui-cui Shan, Teck-peng LohAbstract:A palladium-catalyzed dialkylation of 1,3-dien-5-ynes was developed using alkenyl double bonds as the initiator and terminator for the synthesis of functionalized indene derivatives. The reactions were performed under mild reaction conditions, affording the corresponding multi-substituted indene derivatives in high efficiency via unprecedented 5-Endo Cyclization and alkylation processes. It was found that the substituent location at the alkenyl double bond was essential for the chemoselective synthesis of the indene and naphthalene derivatives, respectively
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Palladium-Catalyzed One-Pot Highly Regioselective 6-Endo Cyclization and Alkylation of Enynoates: Synthesis of 2‑Alkanone Pyrones
2018Co-Authors: Tanveer Ahmad, Sheng-qi Qiu, Teck-peng LohAbstract:The Pd(II)-catalyzed one-pot tandem Cyclization/alkylation reactions of enynoates with allylic alcohols have been demonstrated. In this reaction, an innovative protocol proceeded well through Pd-catalyzed intramolecular selective 6-Endo Cyclization, insertion of allylic alcohols into the Pd–C bond of vinylpalladium species generated in situ, and β-hydrogen elimination processes. This conversion provides a convenient and efficient methodology for the synthesis of 2-alkanone pyrones in moderate to good yields
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palladium catalyzed difunctionalization of internal alkynes via highly regioselective 6 Endo Cyclization and alkenylation of enynoates synthesis of multisubstituted pyrones
Organic Letters, 2015Co-Authors: Panpan Tian, Saihu Cai, Qiuju Liang, Xingyi Zhou, Teck-peng LohAbstract:An efficient Pd(II)-catalyzed difunctionalization reaction of internal alkynes is reported. In this reaction, various enynoates and electron-deficient alkenes were used for the syntheses of useful highly substituted pyrone derivatives via a 6-Endo Cyclization and subsequent alkenylation pathway. The corresponding products could be obtained in moderate to good yields under very mild reaction conditions. The high regioselectivity and wide compatibility with different functional groups found in the desired products demonstrate this method to be a general and useful tool for the synthesis of highly substituted pyrone derivatives.
Frédéric Schmidt - One of the best experts on this subject based on the ideXlab platform.
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Palladium-Catalyzed Synthesis of 2,3-Disubstituted 5-Azaindoles via Heteroannulation Reaction and of 2-Substituted 5-Azaindoles through Domino Sila-Sonogashira/5-Endo Cyclization
The Journal of organic chemistry, 2012Co-Authors: Marion Livecchi, Géraldine Calvet, Frédéric SchmidtAbstract:A general and efficient procedure for the synthesis of 2,3-disubstituted 5-azaindoles through the palladium-catalyzed heteroannulation of 4-acetamido-3-iodopyridines and diaryl-, dialkyl-, or arylalkylalkynes is described along with a study of the reaction regioselectivity. The preparation of 2-monosubstituted 5-azaindoles via sila-Sonogashira/5-Endo Cyclization is also reported. These methods allowed us to prepare 36 diversely substituted 5-azaindoles in good yields.
Marion Livecchi - One of the best experts on this subject based on the ideXlab platform.
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Palladium-Catalyzed Synthesis of 2,3-Disubstituted 5-Azaindoles via Heteroannulation Reaction and of 2-Substituted 5-Azaindoles through Domino Sila-Sonogashira/5-Endo Cyclization
2016Co-Authors: Marion Livecchi, Géraldine Calvet, Frédéric SchmidtAbstract:A general and efficient procedure for the synthesis of 2,3-disubstituted 5-azaindoles through the palladium-catalyzed heteroannulation of 4-acetamido-3-iodopyridines and diaryl-, dialkyl-, or arylalkylalkynes is described along with a study of the reaction regioselectivity. The preparation of 2-monosubstituted 5-azaindoles via sila-Sonogashira/5-Endo Cyclization is also reported. These methods allowed us to prepare 36 diversely substituted 5-azaindoles in good yields
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Palladium-Catalyzed Synthesis of 2,3-Disubstituted 5-Azaindoles via Heteroannulation Reaction and of 2-Substituted 5-Azaindoles through Domino Sila-Sonogashira/5-Endo Cyclization
The Journal of organic chemistry, 2012Co-Authors: Marion Livecchi, Géraldine Calvet, Frédéric SchmidtAbstract:A general and efficient procedure for the synthesis of 2,3-disubstituted 5-azaindoles through the palladium-catalyzed heteroannulation of 4-acetamido-3-iodopyridines and diaryl-, dialkyl-, or arylalkylalkynes is described along with a study of the reaction regioselectivity. The preparation of 2-monosubstituted 5-azaindoles via sila-Sonogashira/5-Endo Cyclization is also reported. These methods allowed us to prepare 36 diversely substituted 5-azaindoles in good yields.
Bijoy Kundu - One of the best experts on this subject based on the ideXlab platform.
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synthesis of triazolo isoquinolines and isochromenes from 2 alkynylbenzaldehyde via domino reactions under transition metal free conditions
Journal of Organic Chemistry, 2013Co-Authors: Ravi Kiran Arigela, Srinivas Samala, Rohit Mahar, Sanjeev K Shukla, Bijoy KunduAbstract:We describe two simple straightforward syntheses of triazolo isoquinolines (3) and isochromenes (7) from 2-alkynylbenzaldehydes (1) as a common synthon. The synthetic strategy for 3 involves formation of the (E)-1-(2-nitrovinyl)-2-(alkynyl)benzene species 2 via condensation of synthon 1 with nitromethane followed by a [3 + 2] cycloaddition/extrusion of the nitro group/regioselective 6-Endo Cyclization domino sequence. In yet another strategy, the synthon 1 was condensed with nitromethane followed by electrophilic iodo Cyclization of the resulting 2-nitro-1-(2-(alkynyl)phenyl)ethanol (6) to furnish iodo isochromene derivatives. The salient feature of the above two strategies involves formation of the corresponding heterocycles under metal-free conditions in good yields.
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counter ion effect in au ag catalyzed chemoselective 6 Endo dig n and o Cyclizations of enyne urea system diversity oriented synthesis of annulated indoles
Journal of Organic Chemistry, 2013Co-Authors: Sahaj Gupta, Dipankar Koley, K. Ravikumar, Bijoy KunduAbstract:A two-step protocol for the diversity-oriented synthesis of annulated indoles following MCR-post MCR modification concept is described. The reaction initially proceeds through the annulation of 2-(2,2-dibromovinyl)aniline, an isocyanate, and a terminal alkyne in a three-component tandem format via Cu/Pd-catalyzed cross coupling to afford N-1 and C-2 functionalized indole. In the subsequent step, the enyne–urea derivative undergoes chemo- and regioselective 6-Endo Cyclization to afford O-cyclized product in the presence of Au(I)/AgNO3 and N-cyclized product in the presence of Au(I)/AgOTf under a post-MCR modification step. A mechanistic investigation following a recent pioneering work on the silver effect in gold catalysis (Shi, X. J. Am. Chem. Soc. 2012, 134, 9012) explains the role of counterion on Au/Ag-catalyzed regiodivergent pathways.
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Synthesis of Triazolo Isoquinolines and Isochromenes from 2‑Alkynylbenzaldehyde via Domino Reactions under Transition-Metal-Free Conditions
2013Co-Authors: Ravi Kiran Arigela, Srinivas Samala, Rohit Mahar, Sanjeev K Shukla, Bijoy KunduAbstract:We describe two simple straightforward syntheses of triazolo isoquinolines (3) and isochromenes (7) from 2-alkynylbenzaldehydes (1) as a common synthon. The synthetic strategy for 3 involves formation of the (E)-1-(2-nitrovinyl)-2-(alkynyl)benzene species 2 via condensation of synthon 1 with nitromethane followed by a [3 + 2] cycloaddition/extrusion of the nitro group/regioselective 6-Endo Cyclization domino sequence. In yet another strategy, the synthon 1 was condensed with nitromethane followed by electrophilic iodo Cyclization of the resulting 2-nitro-1-(2-(alkynyl)phenyl)ethanol (6) to furnish iodo isochromene derivatives. The salient feature of the above two strategies involves formation of the corresponding heterocycles under metal-free conditions in good yields
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Application of the modified Pictet-Spengler Cyclization reaction for the preparation of an imidazopyrazine ring: synthesis of new pyrido- and pyrimido-imidazopyrazines.
Journal of combinatorial chemistry, 2009Co-Authors: Sunil K. Sharma, Bijoy KunduAbstract:An efficient and versatile method for the synthesis of imidazopyrazine ring using the modified Pictet−Spengler strategy has been reported. The two step strategy offers rapid assembly of druglike core templates pyridine or pyrimidine and imidazole into new annulated polycyclic skeletons: pyrido- and pyrimido-imidazopyrazines. The rate of Endo Cyclization of aryl/heteroaryl-amine substrates has been compared with traditionally used aliphatic amine substrates, and results have been discussed in the light of the pKa values of amines present in each substrate.
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application of the pictet spengler reaction to aryl amine based substrates having pyrimidine as a π nucleophile synthesis of pyrimidoquinolines with structural analogy to benzonaphthyridines present in alkaloids
ChemInform, 2009Co-Authors: Piyush K Agarwal, Sudhir K Sharma, Devesh Sawant, Bijoy KunduAbstract:Abstract Synthesis of pyrimidine annulated quinolines, structurally analogous to biologically active benzonaphthyridines present in alkaloids, has been described. Our synthetic strategy is based on the modified Pictet–Spengler reaction involving substrates comprising deactivated pyrimidine ring as the nucleophilic partner whereas aryl amine originating from the C-4 of the pyrimidine ring served as the source for electrophilic partner. The resulting substrates 5 – 7 with diversity at 2- and 6-position after condensation with a variety of aldehydes underwent 6- Endo Cyclization to furnish pyrimido[5,4- c ]quinolines 14 in good yields. However, attempts to further extend this strategy on new structurally analogous substrate involving the pyridine ring as nucleophilic partner failed, thus limiting the scope of the reaction.