A new and stereoselective synthetic approach to spirooxindole 4H-pran-2-one derivatives with three contiguous stereogenic centers has been developed via an NHC-catalyzed three-component domino reaction of alkynyl aldehydes with oxindoles. The reaction proceeds smoothly in good yields with good to high diastereoselectivities. These novel heterocyclic spirooxindoles may provide promising candidates for drug discovery. Additionally, a possible mechanism for the entire reaction sequence is proposed.

No abstract

Reported here is a novel photoinduced strategy for the borylation of aryl sulfonium salts using bis­(pinacolato)­diboron as the boron source. This method exploits redox-neutral aryl sulfoniums to gain access to aryl radicals via C–S bond activation upon photoexcitation under transition-metal-free conditions. Therefore, it grants access to diverse arylboronate esters with good performance from easily available aryl sulfoniums accompanied by mild conditions, operational simplicity, and easy scalability.

No abstract

An efficient and practical transition-metal-free synthesis of 2-substituted benzo[b]furans catalyzed by readily accessible base was developed with broad substrates scope.

A mild and efficient two-step synthesis of 3-substituted β-carbolinone derivatives from 3-substituted β-carboline in good yields is described. A possible reaction mechanism for the formation of the skeleton of β-carbolin-1-one is proposed. The structures of these compounds were established by IR, 1H-NMR, 13C-NMR, mass spectrometry and elemental analysis, as well as X-ray crystallographic analysis of 4-2 and 6-2.

No abstract

A novel and regioselective umpolung synthesis of spirooxindoles has been developed by cooperative NHC-Lewis acid-mediated formal [3 + 2] annulations of alkynyl aldehydes with isatins. In most cases, the reactions proceeded via a(3)-d(3) umpolung of alkynyl aldehydes resulting in spirooxindole butenolides. In a few cases, spirooxindole furan-3(2H)-ones were formed as the major products via an a(1)-d(1) umpolung process by controlling the reaction temperature. These newly formed spirooxindoles could provide promising candidates for chemical biology and drug lead discovery.