Iron-Catalyzed Cycloaddition of Alkynenitriles and Alkynes
摘要:
The combination of Fe(OAc)(2) and an electron-donating, sterically hindered pyridyl bisimine ligand catalyzes the cycloaddition of alkynenitriles and alkynes. A variety of substituted pyridines were obtained in good yields.
A hydroarylativecoupling of internalalkynes with indolines and tetrahydroquinolines has been developed using the bench‐stable and inexpensive ruthenium (II) catalyst. The applicability of this methodology has been demonstrated by the late stage functionalization of natural products, biologically active molecules, and APIs.
The synthesis of pyridines through direct intermolecular cycloaddition of alkynes and nitriles is a contemporary challenge in organic synthesis. A Brønsted acid mediated formal [2+2+2] cycloaddition of heteroalkynes and nitriles was developed that proceeds under mild conditions. This constitutes a modular approach to highly substituted pyridine cores.
Attempts at vinyl radical carbonylation through cyclization onto carbonyl and cyano groups
作者:Pier Carlo Montevecchi、Maria Luisa Navacchia、Piero Spagnolo
DOI:10.1016/s0040-4020(98)00458-x
日期:1998.7
Sulfanylvinyl radicals 4–6, 16, produced from toluenesulfanyl radical addition to alkynes 1–3, 15, gave only products arising from cyclizationonto the thiophenyl ring and H-abstraction. No products were obtained deriving from possible 5-membered cyclizationonto the esteric or thioesteric carbonyl group. Similar results were obtained from toluenesulfanyl radical addition to alkynyl nitriles 20 and
Direct Photoexcitation of Ethynylbenziodoxolones: An Alternative to Photocatalysis for Alkynylation Reactions**
作者:Stephanie G. E. Amos、Diana Cavalli、Franck Le Vaillant、Jerome Waser
DOI:10.1002/anie.202110257
日期:2021.10.25
Ethynylbenziodoxolones (EBXs) are commonly used as radical traps in photocatalytic alkynylations. Herein, we report that aryl-substituted EBXreagents can be directly activated by visible light irradiation. They act as both oxidants and radical traps, alleviating the need for a photocatalyst in several reported EBX-mediated processes, including decarboxylative and deboronative alkynylations, the oxyalkynylation
Copper-catalysed Csp<sup>3</sup>–Csp cross-couplings between cyclobutanone oxime esters and terminal alkynes induced by visible light
作者:Binlin Zhao、Yixiao Wu、Yu Yuan、Zhuangzhi Shi
DOI:10.1039/d0cc00988a
日期:——
copper-catalysed C-C bond cleavage. This approach was applied to prepare a series of highly functionalized alkynyl nitriles using readily available cyclobutanones and terminal alkynes. Mechanistic exploration showed that the in situgeneratedcopperacetylide complex is an effective photosensitive catalyst to promote the C-C bond cleavage of cycloketoxime esters through a radical process.