Liu, Rui-Juan; Wang, Peng-Fei; Yuan, Wen-Kui; Wen, Li-Rong; Li, Ming published an article in 2017, the title of the article was Nickel Catalysis Enables Hetero [2+2+1] Cycloaddition between Yne-Isothiocyanates and Isonitriles with Low Catalyst Loading.Electric Literature of 157869-15-3 And the article contains the following content:
Nickel(II) can be used to catalyze the hetero [2+2+1] cycloaddition of 2-alkynylaryl isothiocyanates and isonitriles in 2-methyltetrahydrofuran (2-MeTHF) to give a wide array of thieno[2,3-b]indoles in excellent yields. The reaction is featured by employing as little as 0.3 mol% nickel(II) acetylacetonate [Ni(acac)2] under air conditions in the absence of any additives (addnl. reducing agents and external ligands). This is the first successful example to apply nickel(II) directly in hetero [2+2+1] cycloadditions The experimental process involved the reaction of 2-((4-Methoxyphenyl)ethynyl)aniline(cas: 157869-15-3).Electric Literature of 157869-15-3
The Article related to alkynylaryl isothiocyanate isonitrile nickel hetero cycloaddition catalyst, thienoindole preparation, Heterocyclic Compounds (More Than One Hetero Atom): Fused-Ring Systems With Two Or More Hetero Atoms, No More Than One Hetero Atom Per Ring and other aspects.Electric Literature of 157869-15-3
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem