36634-78-3Relevant academic research and scientific papers
Visible-Light-Enabled Aerobic Denitrative C3-Alkenylation of Indoles with β-Nitrostyrenes
Chawla, Ruchi,Kapoor, Ritu,Yadav, Lal Dhar S.
supporting information, p. 1394 - 1399 (2020/10/02)
Herein, we unveil the first visible-light-mediated alkenylation reaction of indoles. The reaction follows a denitrative radical pathway where β-nitrostyrenes have been utilized as the alkene precursors for the C3-styrenylation of indoles under visible-light irradiation to afford biologically and synthetically important 3-alkenylindoles. High regioselectivity, absence of any photocatalyst, metal, external oxidant, acid or base, and the use of visible light and air as inexpensive clean reagents are the key highlights of the developed method.
Chiral Imidodiphosphoric Acid-Catalyzed Highly Diastereo- and Enantioselective Synthesis of Poly-Substituted 3,4-Dihydro-2 H-pyrans: [4 + 2] Cycloadditions of β,γ-Unsaturated α-Ketoesters and 3-Vinylindoles
Guan, Xu-Kai,Liu, Guo-Feng,An, Dong,Zhang, Heng,Zhang, Suo-Qin
supporting information, p. 5438 - 5442 (2019/08/01)
Imidodiphosphoric acids were employed to catalyze inverse-electron-demand hetero-Diels-Alder reaction of β,γ-unsaturated α-ketoesters and 3-vinylindoles. A series of optically active 3,4-dihydro-2H-pyran derivatives with three contiguous stereogenic centers was synthesized in excellent yields (70-99%), diastereoselectivities (>20:1), and enantioselectivities (73-99%). The resulting indole containing 3,4-dihydro-2H-pyran could be converted to tetrahydropyran derivatives, which appear in several biological active compounds by simple hydrogenation reduction.
Transition-Metal-Free Redox-Neutral One-Pot C3-Alkenylation of Indoles Using Aldehydes
Sahu, Samrat,Banerjee, Ankush,Maji, Modhu Sudan
, p. 464 - 467 (2017/02/10)
The synthesis of sensitive β-alkyl 3-vinylindoles having diverse functional groups with good selectivity remains a challenging task. Keeping the synthetic utility of 3-alkenylindoles in mind, we explored a unique approach to synthesize them from unprotected indoles in a domino fashion. A transition-metal-free C3-alkenylation of indole is reported by using sequential Br?nsted acid/base catalysis. Several β-substituted 3-alkenylindoles and conjugated 1,3-dienes are synthesized by direct coupling of indole and readily available aliphatic aldehydes. Excellent scalability and recycling of benzenesulfinic acid for successive alkenylation reactions up to five times make this method economically viable.
Cobalt-catalysed reductive C-H alkylation of indoles using carboxylic acids and molecular hydrogen
Cabrero-Antonino, Jose R.,Adam, Rosa,Junge, Kathrin,Beller, Matthias
, p. 6439 - 6450 (2017/08/29)
The direct CH-alkylation of indoles using carboxylic acids is presented for the first time. The catalytic system based on the combination of Co(acac)3 and 1,1,1-tris(diphenylphosphinomethyl)-ethane (Triphos, L1), in the presence of Al(OTf)3 as co-catalyst, is able to perform the reductive alkylation of 2-methyl-1H-indole with a wide range of carboxylic acids. The utility of the protocol was further demonstrated through the C3 alkylation of several substituted indole derivatives using acetic, phenylacetic or diphenylacetic acids. In addition, a careful selection of the reaction conditions allowed to perform the selective C3 alkenylation of some indole derivatives. Moreover, the alkenylation of C2 position of 3-methyl-1H-indole was also possible. Control experiments indicate that the aldehyde, in situ formed from the carboxylic acid hydrogenation, plays a central role in the overall process. This new protocol enables the direct functionalization of indoles with readily available and stable carboxylic acids using a non-precious metal based catalyst and hydrogen as reductant.
Condensation of indoles and aldehydes in subcritical water without the addition of catalysts
Hirashita, Tsunehisa,Ogawa, Masaki,Hattori, Reina,Okochi, Sota,Araki, Shuki
, p. 1760 - 1764 (2016/01/27)
A series of 3,3′-diindolylmethanes were prepared in high yields from indoles and aldehydes under subcritical water conditions without the addition of catalysts. 3-Alkenylindoles were also obtained in good yields from aldehydes bearing benzylic hydrogen atoms.
Silica-supported policresulen as a solid acid catalyst for organic reactions
Zeng, Kexing,Huang, Zhipeng,Yang, Jie,Gu, Yanlong
, p. 1606 - 1613 (2015/09/15)
A new type of solid catalyst was prepared by coating a thin layer of policresulen, an inexpensive polymer prepared via condensation of 2-hydroxy-4-methylbenzenesulfonic acid and formaldehyde that has been used as commercially available drug, onto the surface of silica. The policresulen component is insoluble in many organic solvents and can be adsorbed on silica with the aid of hydrogen bonding. The obtained silica/policresulen composite showed remarkable catalytic activity for various organic reactions. In model reactions, the catalyst can be recycled several times without significant loss of activity. The salient features of using this acid catalyst in organic reactions include cost-effectiveness, simple and time-efficient preparation, and the convenience of controlling the acid loading on the solid.
FeCl3?6H2O-catalyzed alkenylation of indoles with aldehydes
Yang, Qin,Wang, Liandi,Guo, Tenglong,Yu, Zhengkun
, p. 8355 - 8361 (2013/01/15)
FeCl3?6H2O-catalyzed efficient C3-alkenylation of indoles was realized through the condensation of aldehydes and indole derivatives in the presence of 2 equiv of ethanol at ambient temperature, forming 3- vinylindoles in up to 93% yields. Ethanol promoted formation of the desired products. An obvious solvent effect was observed, and bisindoles were identified as the reaction intermediates.
Phosphine-mediated coupling of gramines with aldehydes: A remarkably simple synthesis of 3-vinylindoles
Kam, Hung Low,Magomedov, Nabi A.
, p. 2003 - 2005 (2007/10/03)
(Chemical Equation Presented) A new and practical synthesis of terminally substituted 3-vinylindoles is described involving tributylphosphine-mediated coupling of gramines with aldehydes.
