The Experts below are selected from a list of 912 Experts worldwide ranked by ideXlab platform
B Sridhar - One of the best experts on this subject based on the ideXlab platform.
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gold catalyzed synthesis of 1h Isochromene 4 carbaldehydes via oxidative cascade cyclization
Organic and Biomolecular Chemistry, 2021Co-Authors: Galla V Karunakar, Chittala Emmaniel Raju, Veerabhushanam Kadiyala, Gottam Sreenivasulu, Perla Bharathkumar, B SridharAbstract:An efficient gold-catalyzed formation of indenylidene-derived 1H-Isochromene-4-carbaldehydes from substituted 1,5,10-triyne-O-silanes was developed under mild reaction conditions. In this reaction gold- catalyzed selective oxidation, 1,2-migration of enynyl group, nucleophilc addition and then 5-endo-dig cyclization took place regioselectively. The indenylidene-derived Isochromene-4-carbaldehydes were synthesized in moderate to very good yields via the formation of a new C-C and C-O bonds in one-pot.
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Tandem Prins and Friedel–Crafts Cyclizations for the Stereoselective Synthesis of trans-Fused Hexahydro-1H-benzo[g]Isochromene Derivatives
Synthesis, 2015Co-Authors: B. V. Subba Reddy, Ch. Syama Sundar, M. V. Ramana Reddy, C. Suresh Reddy, B SridharAbstract:Aldehydes and ketones undergo smooth coupling with (4 E )-3-benzyl-5-phenylpent-4-en-1-ol in the presence of scandium(III) triflate (10 mol%) and 4-toluenesulfonic acid (30 mol%) to give the corresponding trans -fused hexahydro-1 H -benzo[ g ]Isochromenes in good yields with excellent selectivity. This is the first example of the synthesis of a trans -fused hexahydro-1 H -benzo[ g ]Isochromene derivatives from an aldehyde and (4 E )-3-benzyl-5-phenylpent-4-en-1-ol through tandem Prins and Friedel–Crafts cyclizations.
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tandem prins and friedel crafts cyclizations for the stereo selective synthesis of trans fused hexahydro 1h benzo g Isochromene derivatives
Synthesis, 2015Co-Authors: B Subba V Reddy, Ch. Syama Sundar, M Ramana V Reddy, Suresh C Reddy, B SridharAbstract:Aldehydes and ketones undergo smooth coupling with (4 E )-3-benzyl-5-phenylpent-4-en-1-ol in the presence of scandium(III) triflate (10 mol%) and 4-toluenesulfonic acid (30 mol%) to give the corresponding trans -fused hexahydro-1 H -benzo[ g ]Isochromenes in good yields with excellent selectivity. This is the first example of the synthesis of a trans -fused hexahydro-1 H -benzo[ g ]Isochromene derivatives from an aldehyde and (4 E )-3-benzyl-5-phenylpent-4-en-1-ol through tandem Prins and Friedel–Crafts cyclizations.
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A novel Prins reaction for the synthesis of hexahydro-8,8-dimethyl-1H-isochromen-7-ol derivatives
Tetrahedron Letters, 2014Co-Authors: B. V. Subba Reddy, S. Rehana Anjum, G. Madhusudhan Reddy, B SridharAbstract:Abstract Various aldehydes undergo smooth coupling with 5-(hydroxymethyl)-4,6,6-trimethylcyclohex-3-enol in the presence of p-TSA at ambient temperature to afford a novel series of hexahydro-8,8-dimethyl-1H-isochromen-7-ol derivatives in good yields with high selectivity. This is the first report on the synthesis of isochromen-7-ol derivatives via the Prins reaction.
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the prins cascade cyclization reaction for the synthesis of angularly fused tetrahydropyran and piperidine derivatives
European Journal of Organic Chemistry, 2013Co-Authors: B Subba V Reddy, Harish Kumar, J S Yadav, B SridharAbstract:2-Arylethylbut-3-en-1-ol is found to undergo smooth Prins cascade reactions with various aldehydes in the presence of Sc(OTf)3 (10 mol-%) and a stoichiometric amount of TsOH to afford the corresponding trans-fused hexahydro-1H-benzo[f]Isochromenes in good yields with excellent selectivity. Likewise, N-tosyl-2-phenethylbut-3-en-1-amine gives trans-fused octahydrobenzo[f]isoquinoline derivatives under similar conditions. This is the first example of the synthesis of hexahydro-1H-benzo[f]Isochromene and octahydrobenzo-[f]isoquinoline from 2-arylethylbut-3-en-1-ol and N-tosyl-2-phenethylbut-3-en-1-amine, respectively.
Dieter Enders - One of the best experts on this subject based on the ideXlab platform.
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one pot synthesis of 1 substituted 1h Isochromenes by combining bronsted acid with silver catalysis
Synthesis, 2016Co-Authors: Nina Felicitas Brohl, Dipti Sankar Kundu, Gerhard Raabe, Dieter EndersAbstract:A one-pot synthesis of 1-substituted 1 H -Isochromenes employing various 2-alkynyl-benzaldehydes and ketones as substrates under a combination of Bronsted acid and silver catalysis has been developed. The Isochromenes, which are present as important heterocyclic core structures in many bioactive and natural compounds, are obtained in medium to excellent yields with diastereomeric ratios of up to 9:1. A first enantioselective variant has also been tested.
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asymmetric synthesis of 3 substituted hexahydro 3h Isochromenes via an organocatalytic triple cascade yb catalyzed hetero diels alder sequence
Synthesis, 2012Co-Authors: Nico Erdmann, Iuliana Atodiresei, Dieter EndersAbstract:An efficient two-step asymmetric synthesis of highly substituted 3-alkoxy-hexahydro-3 H -Isochromenes and 3-sulfenylated hexahydro-3 H -Isochromenes is described. The procedure involves an organocatalytic triple cascade reaction, followed by an intermolecular [Yb(fod) 3 ]-catalyzed inverse-electron-demand hetero-Diels–Alder reaction. Using this strategy, a total of six stereogenic centers are obtained with excellent diastereoselectivities and virtually complete enantioselectivities (>95:5 dr, >99% ee).
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Asymmetric Synthesis of 3-Substituted Hexahydro-3H-Isochromenes via an Organocatalytic Triple Cascade/Yb-Catalyzed Hetero-Diels–Alder Sequence
Synthesis, 2012Co-Authors: Nico Erdmann, Iuliana Atodiresei, Dieter EndersAbstract:An efficient two-step asymmetric synthesis of highly substituted 3-alkoxy-hexahydro-3 H -Isochromenes and 3-sulfenylated hexahydro-3 H -Isochromenes is described. The procedure involves an organocatalytic triple cascade reaction, followed by an intermolecular [Yb(fod) 3 ]-catalyzed inverse-electron-demand hetero-Diels–Alder reaction. Using this strategy, a total of six stereogenic centers are obtained with excellent diastereoselectivities and virtually complete enantioselectivities (>95:5 dr, >99% ee).
Yu Zhou - One of the best experts on this subject based on the ideXlab platform.
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Rh(III)-Catalyzed Dual C-H Functionalization/Cyclization Cascade by a Removable Directing Group: A Method for Synthesis of Polycyclic Fused Pyrano[de]Isochromenes.
The Journal of organic chemistry, 2020Co-Authors: Zhihao Shu, Jianhui Zhou, Yilang Cheng, Hong Liu, Dechuan Wang, Yu ZhouAbstract:An interesting Rh(III)-catalyzed dual C-H functionalization/cyclization cascade of azomethine imine with diazophosphonate by a removable directing group for the synthesis of highly fused pyrano[de]Isochromene has been achieved. The transformation shows that the desired pyrano[de]Isochromenes with two oxygen atoms on its core scaffold could be constructed with good to excellent yields (up to 86%) via a facile one-pot, multiple-step cascade reaction, along with broad generality and versatility.
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rh iii catalyzed dual c h functionalization cyclization cascade by a removable directing group a method for synthesis of polycyclic fused pyrano de Isochromenes
Journal of Organic Chemistry, 2020Co-Authors: Zhihao Shu, Jianhui Zhou, Yilang Cheng, Hong Liu, Dechuan Wang, Yu ZhouAbstract:An interesting Rh(III)-catalyzed dual C-H functionalization/cyclization cascade of azomethine imine with diazophosphonate by a removable directing group for the synthesis of highly fused pyrano[de]Isochromene has been achieved. The transformation shows that the desired pyrano[de]Isochromenes with two oxygen atoms on its core scaffold could be constructed with good to excellent yields (up to 86%) via a facile one-pot, multiple-step cascade reaction, along with broad generality and versatility.
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silver catalyzed intramolecular cyclization of o 1 alkynyl benzamides efficient synthesis of 1h isochromen 1 imines
Advanced Synthesis & Catalysis, 2009Co-Authors: Guannan Liu, Yu Zhou, Dengyou Zhang, Xiao Ding, Hualiang Jiang, Hong LiuAbstract:An efficient avenue for the facile and atom-economic synthesis of (1H)-isochromen-1- imines has been developed, and a broad spectrum of substrates can participate in the process effectively to produce the desired products in good yields. Significantly, this is the first report of the synthesis of (1H)-isochromen-1-imines that involves a silver(I)-catalyzed, regiocontrolled intramolecular addition of the carbonyl group of the amide moiety towards an alkyne.
Hong Liu - One of the best experts on this subject based on the ideXlab platform.
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Rh(III)-Catalyzed Dual C-H Functionalization/Cyclization Cascade by a Removable Directing Group: A Method for Synthesis of Polycyclic Fused Pyrano[de]Isochromenes.
The Journal of organic chemistry, 2020Co-Authors: Zhihao Shu, Jianhui Zhou, Yilang Cheng, Hong Liu, Dechuan Wang, Yu ZhouAbstract:An interesting Rh(III)-catalyzed dual C-H functionalization/cyclization cascade of azomethine imine with diazophosphonate by a removable directing group for the synthesis of highly fused pyrano[de]Isochromene has been achieved. The transformation shows that the desired pyrano[de]Isochromenes with two oxygen atoms on its core scaffold could be constructed with good to excellent yields (up to 86%) via a facile one-pot, multiple-step cascade reaction, along with broad generality and versatility.
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rh iii catalyzed dual c h functionalization cyclization cascade by a removable directing group a method for synthesis of polycyclic fused pyrano de Isochromenes
Journal of Organic Chemistry, 2020Co-Authors: Zhihao Shu, Jianhui Zhou, Yilang Cheng, Hong Liu, Dechuan Wang, Yu ZhouAbstract:An interesting Rh(III)-catalyzed dual C-H functionalization/cyclization cascade of azomethine imine with diazophosphonate by a removable directing group for the synthesis of highly fused pyrano[de]Isochromene has been achieved. The transformation shows that the desired pyrano[de]Isochromenes with two oxygen atoms on its core scaffold could be constructed with good to excellent yields (up to 86%) via a facile one-pot, multiple-step cascade reaction, along with broad generality and versatility.
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silver catalyzed intramolecular cyclization of o 1 alkynyl benzamides efficient synthesis of 1h isochromen 1 imines
Advanced Synthesis & Catalysis, 2009Co-Authors: Guannan Liu, Yu Zhou, Dengyou Zhang, Xiao Ding, Hualiang Jiang, Hong LiuAbstract:An efficient avenue for the facile and atom-economic synthesis of (1H)-isochromen-1- imines has been developed, and a broad spectrum of substrates can participate in the process effectively to produce the desired products in good yields. Significantly, this is the first report of the synthesis of (1H)-isochromen-1-imines that involves a silver(I)-catalyzed, regiocontrolled intramolecular addition of the carbonyl group of the amide moiety towards an alkyne.
Jidong Zhao - One of the best experts on this subject based on the ideXlab platform.
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gold catalyzed oxidative cyclizations of o alkynyl phenyl propargyl silyl ether derivatives involving 1 2 enynyl migration synthesis of functionalized 1h Isochromenes and 2h pyrans
Organic Letters, 2018Co-Authors: Jidong Zhao, Wei Xu, Xiangdong LiAbstract:A new and convenient strategy for the synthesis of functionalized 1H-Isochromene and 2H-pyran derivatives based on gold-catalyzed oxidative cyclizations of o-(alkynyl)phenyl propargyl ether derivatives has been developed. The reaction proceeds via gold-catalyzed highly regioselective oxidation, followed by 1,2-migration of an enynyl group and nucleophlic addition. Isocoumarins were also constructed through oxidative cleavage of the exocyclic double bond of the obtained 1H-Isochromenes.
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Gold-Catalyzed Oxidative Cyclizations of {o-(Alkynyl)phenyl propargyl} Silyl Ether Derivatives Involving 1,2-Enynyl Migration: Synthesis of Functionalized 1H-Isochromenes and 2H-Pyrans
Organic Letters, 2018Co-Authors: Jidong Zhao, Wei Xu, Xiangdong LiAbstract:A new and convenient strategy for the synthesis of functionalized 1H-Isochromene and 2H-pyran derivatives based on gold-catalyzed oxidative cyclizations of o-(alkynyl)phenyl propargyl ether derivatives has been developed. The reaction proceeds via gold-catalyzed highly regioselective oxidation, followed by 1,2-migration of an enynyl group and nucleophlic addition. Isocoumarins were also constructed through oxidative cleavage of the exocyclic double bond of the obtained 1H-Isochromenes.
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Gold-Catalyzed Oxidative Cyclizations of {o-(Alkynyl)phenyl propargyl} Silyl Ether Derivatives Involving 1,2-Enynyl Migration: Synthesis of Functionalized 1H-Isochromenes and 2H-Pyrans
Organic letters, 2018Co-Authors: Jidong Zhao, Xin Xie, Ning Sun, Yuanhong LiuAbstract:A new and convenient strategy for the synthesis of functionalized 1H-Isochromene and 2H-pyran derivatives based on gold-catalyzed oxidative cyclizations of o-(alkynyl)phenyl propargyl ether derivat...
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gold catalyzed oxidative cyclizations of o alkynyl phenyl propargyl silyl ether derivatives involving 1 2 enynyl migration synthesis of functionalized 1h Isochromenes and 2h pyrans
Organic Letters, 2018Co-Authors: Jidong Zhao, Xin Xie, Ning Sun, Yuanhong LiuAbstract:A new and convenient strategy for the synthesis of functionalized 1H-Isochromene and 2H-pyran derivatives based on gold-catalyzed oxidative cyclizations of o-(alkynyl)phenyl propargyl ether derivat...
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Gold-Catalyzed Oxidative Cyclizations of {o‑(Alkynyl)phenyl propargyl} Silyl Ether Derivatives Involving 1,2-Enynyl Migration: Synthesis of Functionalized 1H‑Isochromenes and 2H‑Pyrans
2018Co-Authors: Jidong Zhao, Xin Xie, Ning Sun, Yuanhong LiuAbstract:A new and convenient strategy for the synthesis of functionalized 1H-Isochromene and 2H-pyran derivatives based on gold-catalyzed oxidative cyclizations of o-(alkynyl)phenyl propargyl ether derivatives has been developed. The reaction proceeds via gold-catalyzed highly regioselective oxidation, followed by 1,2-migration of an enynyl group and nucleophlic addition. Isocoumarins were also constructed through oxidative cleavage of the exocyclic double bond of the obtained 1H-Isochromenes
