Cited by C–H Activation-Engaged Synthesis of Diverse Fused-Heterocycles from the Reactions of 3-Phenyl-1,2,4-oxadiazol-5(2<i>H</i>)-ones with Vinylene Carbonate

Polycyclic Pyrazoles from Alkynyl Cyclohexadienones and Nonstabilized Diazoalkanes via [3 + 2]-Cycloaddition/[1,5]-Sigmatropic Rearrangement/Aza-Michael Reaction Cascade DOI

Raj Patel,

Priyankar Jha,

Anil Chauhan

et al.

Organic Letters, Journal Year: 2024, Volume and Issue: 26(4), P. 839 - 844

Published: Jan. 22, 2024

An efficient method for the stereoselective synthesis of "all center substituted" polycyclic pyrazoles from alkynyl cyclohexa-2,5-dienones and nonstabilized diazoalkanes via sequential [3 + 2]-cycloaddition/[1,5]-sigmatropic rearrangement aza-Michael reactions is reported. The developed process highly regioselective stereoselective. It employs a wide substrate scope to furnish structurally diverse linear bridged [4.4.n.0] ring-fused in moderate good yields. One-pot gram-scale syntheses synthetic transformations have also been showcased.

Language: Английский

Citations

Arylation/Intramolecular Conjugate Addition of 1,6-Enynes Enabled by Manganese(I)-Catalyzed C–H Bond Activation DOI

Yun‐Xuan Tan,

Xingyu Liu,

Yi‐Shuang Zhao

et al.

Organic Letters, Journal Year: 2018, Volume and Issue: 21(1), P. 5 - 9

Published: Nov. 9, 2018

An arylation/intramolecular conjugate addition of cyclohexadienone-containing 1,6-enynes has been established through initiation by manganese(I)-catalyzed C–H bond activation. This tandem reaction involved unusual E/Z-isomerized alkenyl-Mn intermediates and proceeded smoothly with high chemoselectivities perfect atom economy. The cyclization products could be further transformed to various structures. Mechanistic studies suggested that cleavage the was in turnover-limiting step, a manganese carbene anion intermediate proposed explain such an E/Z isomerization process.

Language: Английский

Citations

Chemodivergent Oxidative Annulation of Benzamides and Enynes via 1,4-Rhodium Migration DOI

Jiaqiong Sun, Dachang Bai, Peiyuan Wang

et al.

Organic Letters, Journal Year: 2019, Volume and Issue: 21(6), P. 1789 - 1793

Published: Feb. 22, 2019

Chemodivergent annulative couplings have been realized between N-methoxy benzamides and 1,3-enynes via Rh-catalyzed C-H activation 1,4-Rh migration. Under Rh/copper catalyzed aerobic conditions, the nitrogen annulation occurred as major pathway. The chemoselectivity was switched to oxygen under proper condition control with stoichiometric amounts of Cu(II) oxidant NaOAc. Both coupling systems proceeded a broad scope functional group tolerance.

Language: Английский

Citations

Manganese‐Catalysed C−H Activation: A Regioselective C−H Alkenylation of Indoles and other (hetero)aromatics with 4‐Hydroxy‐2‐Alkynoates Leading to Concomitant Lactonization DOI

Anil Kumar, Nachimuthu Muniraj, Kandikere Ramaiah Prabhu

et al.

Advanced Synthesis & Catalysis, Journal Year: 2019, Volume and Issue: 361(21), P. 4933 - 4940

Published: Aug. 1, 2019

Abstract A manganese‐catalyzed C−H bond alkenylation of indoles at C2‐position with 4‐hydroxy‐2‐alkynoates leading to concomitant lactonization under removable directing group strategy has been disclosed. This exhibits regioselectivity, a broad substrate scope, and good functional tolerance furnishing the products in low high yields. The regioselectivity is guided by electronic effect ester as well steric bulk C4‐position 4‐hydroxy‐2‐alkynoates. After reaction, readily removed obtain N−H free indole. magnified image

Language: Английский

Citations

Palladium-Catalyzed C-2 and C-3 Dual C–H Functionalization of Indoles: Synthesis of Fluorinated Isocryptolepine Analogues DOI

Chen Chen,

Yuebo Wang,

Xiaonan Shi

et al.

Organic Letters, Journal Year: 2020, Volume and Issue: 22(11), P. 4097 - 4102

Published: May 27, 2020

Here we report a protocol to synthesize diversiform fluorinated isocryptolepine analogues with potential biological activities in one step via directed C-2 and C-3 dual C-H functionalization of indoles. We also attempted take into account imidoyl chlorides as novel kind synthons the reactions. As result, variety were obtained up 96% yield. Moreover, conducted control experiments disclose reaction mechanism.

Language: Английский

Citations

Highly Enantioselective Rhodium-Catalyzed Cross-Addition of Silylacetylenes to Cyclohexadienone-Tethered Internal Alkynes DOI

Chang-Lin Duan,

Yun‐Xuan Tan, Junli Zhang

et al.

Organic Letters, Journal Year: 2019, Volume and Issue: 21(6), P. 1690 - 1693

Published: March 1, 2019

The first highly enantioselective rhodium-catalyzed cross-addition of silylacetylenes to cyclohexadienone-tethered internal alkynes has been achieved via a tandem process: regioselective alkynylation the and subsequent intramolecular conjugate addition cyclohexadienones, affording cis-hydrobenzofuran frameworks with good yields (up 88% yield) excellent enantioselectivities (90%–96% ee). This mild reaction showed perfect atom economy broad functional group tolerance. Furthermore, gram-scale experiment diverse further conversions cyclization products were also presented.

Language: Английский

Citations

Manganese(I)‐Catalyzed Site‐Selective C6‐Alkenylation of 2‐Pyridones Using Alkynes via C−H Activation DOI

Shanhong Wan,

Zhenli Luo,

Xin Xu

et al.

Advanced Synthesis & Catalysis, Journal Year: 2021, Volume and Issue: 363(10), P. 2586 - 2593

Published: March 9, 2021

Abstract A Mn(I)‐catalyzed chelation‐assisted direct C6−H alkenylation of 2‐pyridones with both terminal and internal alkynes in a highly regio‐ stereo‐selective manner has been developed. The catalytic system consisting Mn(CO) 5 Br catalyst KOAc additive allows 1‐(2‐pyridyl)‐2‐pyridones to undergo various methyl tert ‐butyl ether (MTBE) furnish the C6‐alkenylated 2‐pyridone products high yields, occurs CH 2 Cl at increased loadings. Mechanistic studies suggest involvement five‐membered organomanganese as key intermediate cycle. magnified image

Language: Английский

Citations

Diverse reactivity of alkynes in C–H activation reactions DOI

Shyam Kumar Banjare, Pranav Shridhar Mahulkar, Tanmayee Nanda

et al.

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(74), P. 10262 - 10289

Published: Jan. 1, 2022

The metal–carbon bond generated through C–H activation is a key organometallic intermediate, which could be further functionalized with various reacting partners. Among the coupling partners used in metal-catalysed activation, alkynes occupy prominent position on account of their varied reactivity.

Language: Английский

Citations

Rh(III)-Catalyzed Coupling of Acrylic Acids and Ynenones via Olefinic C–H Activation and Michael Addition DOI

Yuqin Jiang,

Pengfei Li, Juanjuan Wang

et al.

Organic Letters, Journal Year: 2019, Volume and Issue: 22(2), P. 438 - 442

Published: Dec. 30, 2019

Rh(III)-catalyzed coupling between acrylic acids and yndienones has been realized for the synthesis of cis-hydrobenzofuranone. The reaction proceeded in excellent regio- stereoselectivity under mild redox-neutral conditions via a sequence carboxylic acid-directed olefinic C-H activation, alkyne insertion, Michael addition. Representative products were found to exhibit cytotoxicity toward A549 cancer cell line at micromolar levels.

Language: Английский

Citations

Synthesis of Indole-Fused Oxepines via C–H Activation Initiated Diastereoselective [5 + 2] Annulation of Indoles with 1,6-Enynes DOI

Xiaoli Huang, Yan Shi, Yongzhuang Wang

et al.

Organic Letters, Journal Year: 2021, Volume and Issue: 23(21), P. 8365 - 8369

Published: Oct. 15, 2021

A rhodium-catalyzed diastereoselective formal [5 + 2] annulation of indoles with cyclohexadienone-containing 1,6-enynes has been established via indole 2,3-difunctionalization. The reaction, probably proceeding through tandem C2–H alkenylation and intramolecular Friedel–Crafts alkylation relay, provides rapid construction indole-fused oxepines in good to excellent yields a broad substrate scope. This method also features concomitant cis-hydrobenzo[b] oxepine scaffolds, core unit found numerous natural products important biological activities.

Language: Английский

Citations