40230-91-9Relevant articles and documents
Inverting Conventional Chemoselectivity in the Sonogashira Coupling Reaction of Polyhalogenated Aryl Triflates with TMS-Arylalkynes
Wang, Miao,So, Chau Ming
supporting information, p. 681 - 685 (2022/01/20)
A newly developed phosphine ligand with a C2-cyclohexyl group on the indole ring was successfully applied in a chemoselective Sonogashira coupling reaction with excellent chemoselectivity, affording an inversion of the conventional chemoselectivity order of C–Br > C–Cl > C–OTf. This study also provided an efficient approach to the synthesis of polycyclic aromatic hydrocarbons (PAHs) and the natural product analogue trimethyl-selaginellin L by merging of chemoselective Sonogashira and Suzuki–Miyaura coupling reactions.
Iodocyclisation of Electronically Resistant Alkynes: Synthesis of 2-Carboxy (and sulfoxy)-3-iodobenzo[ b ]thiophenes
Chen, Shuqi,Flynn, Bernard L.
, p. 65 - 76 (2020/11/05)
The iodocyclisation of alkynes bearing tethered nucleophiles is a highly effective method for the construction and diversification of heterocycles. A key limitation to this methodology is the 5-endo-dig iodocyclisation of alkynes that have an unfavourable electronic bias for electrophilic cyclisation. These tend to direct electrophilic attack of the iodonium atom to the wrong carbon for cyclisation, thus favouring competing addition reactions. Using our previously determined reaction conditions for the 5-endo-dig iodocyclisations of electronically resistant alkynes, we have achieved efficient synthetic access to 2-carboxy (and sulfoxy)-3-iodobenzo[b]thiophenes. The corresponding benzo[b]furans and indoles were not accessible under these conditions. This difference may arise due to the availability of a radical mechanism in the case of iodobenzo[b]thiophenes. The 2-carboxy functionality of the iodocyclised products can be further employed in iterative alkyne-coupling iodocyclisation reactions, where the carboxy group or an imine (Schiff base) partakes in a second iodocyclisation to generate a lactone or pyridine ring.
B(C6F5)3-Catalyzed cyclization of alkynes: direct synthesis of 3-silyl heterocyclic compounds
Li, Mengxing,Wang, Ting,An, Zhenyu,Yan, Rulong
supporting information, p. 11953 - 11956 (2020/10/15)
An efficient one-pot strategy for easy access to 3-silyl heterocyclic compounds was developedviaa B(C6F5)3-catalyzed cycloaddition reaction ofo-(1-alkynyl)(thio)anisoles oro-(1-alkynyl)-N-methylaniline. In this reaction, benzenethiophene, benzofuran or indole skeletons could be constructed by an intermolecular cyclization with diphenylsilane. This protocol elicited moderate-to-good yields with metal-free reaction systems.
