85094-87-7Relevant academic research and scientific papers
Iron-Catalyzed Vinylzincation of Terminal Alkynes
Huang, Qiang,Su, Yu-Xuan,Sun, Wei,Hu, Meng-Yang,Wang, Wei-Na,Zhu, Shou-Fei
supporting information, p. 515 - 526 (2022/01/08)
Organozinc reagents are among the most commonly used organometallic reagents in modern synthetic chemistry, and multifunctionalized organozinc reagents can be synthesized from structurally simple, readily available ones by means of alkyne carbozincation. However, this method suffers from poor tolerance for terminal alkynes, and transformation of the newly introduced organic groups is difficult, which limits its applications. Herein, we report a method for vinylzincation of terminal alkynes catalyzed by newly developed iron catalysts bearing 1,10-phenanthroline-imine ligands. This method provides efficient access to novel organozinc reagents with a diverse array of structures and functional groups from readily available vinylzinc reagents and terminal alkynes. The method features excellent functional group tolerance (tolerated functional groups include amino, amide, cyano, ester, hydroxyl, sulfonyl, acetal, phosphono, pyridyl), a good substrate scope (suitable terminal alkynes include aryl, alkenyl, and alkyl acetylenes bearing various functional groups), and high chemoselectivity, regioselectivity, and stereoselectivity. The method could significantly improve the synthetic efficiency of various important bioactive molecules, including vitamin A. Mechanistic studies indicate that the new iron-1,10-phenanthroline-imine catalysts developed in this study have an extremely crowded reaction pocket, which promotes efficient transfer of the vinyl group to the alkynes, disfavors substitution reactions between the zinc reagent and the terminal C–H bond of the alkynes, and prevents the further reactions of the products. Our findings show that iron catalysts can be superior to other metal catalysts in terms of activity, chemoselectivity, regioselectivity, and stereoselectivity when suitable ligands are used.
In situ generation of the Ohira-Bestmann reagent from stable sulfonyl azide: Scalable synthesis of alkynes from aldehydes
Jepsen, Tue Heesgaard,Kristensen, Jesper Langgaard
, p. 9423 - 9426 (2015/02/19)
We report an improved method for in situ generation of the Ohira-Bestmann reagent. Using the recently reported bench-stable imidazole-1-sulfonyl azide as diazotransfer reagent, this new method represents a scalable and convenient approach for the transformation of aldehydes into terminal alkynes. The method features an easier workup compared to the existing in situ protocol due to increased aqueous solubility of waste products.
Tandem cyclopropane ring-opening/conia-ene reactions of 2-alkynyl indoles: A [3 + 3] annulative route to tetrahydrocarbazoles
Grover, Huck K.,Lebold, Terry P.,Kerr, Michael A.
supporting information; experimental part, p. 220 - 223 (2011/03/20)
A Zn(NTf2)2 catalyzed tandem reaction consisting of a nucelophilic ring opening of 1,1-cyclopropanediesters by 2-alkynyl indoles followed by a Conia-ene ring closure results in the efficient one-step synthesis of tetrahydrocarbazoles
Flash Vacuum Pyrolysis of 5-(Indol-2- and -3-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-diones
Benzies, David W. M.,Fresneda, Pilar Martinez,Jones, R. Alan,McNab, Hamish
, p. 1651 - 1654 (2007/10/02)
Flash vacuum pyrolysis of 5-(indol-2- and -3-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-diones results in the initial formation of indolylmethyleneketenes, which generally either lose carbon monoxide to produce ethynylindoles or undergo -sigmatropic shifts, followed by electrocyclic rearrangements, to yield carbazolols or benzindol-5(1H)-one. 5-(Indol-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione and the 3-methylindol-2-yl derivative both yield 3H-pyrroloindol-3-ones via a -sigmatropic rearrangement of the initially formed ketene.
