Transition Metal-Free Domino Hydroamination/Isomerization/Transamidation Sequence: An Entry to Trifluorinated γ-Lactams.

A method for the construction of trifluorinated-5-methylenepyrrolidinone is reported. This strategy combines an acid-catalyzed two-carbon homologation process between ynamides and aldehydes, providing CF-substituted dienes followed by a metal-free domino hydroamination/isomerization/transamidation sequence, delivering trifluorinated-5-methylenepyrrolidinone stereoselectively.

How electrophilic are 3-nitroindoles? Mechanistic investigations and application to a reagentless (4+2) cycloaddition.

The electrophilicity of 4 different 3-nitroindole derivatives has been evaluated by Mayr's linear free energy relationship (log (20 °C) = ( + )) and reveals unexpected values for aromatic compounds, in the nitrostyrene range. 3-Nitroindoles are sufficiently electrophilic to interact with a common diene namely the Danishefsky's diene at room temperature, in the absence of any activator, to furnish smoothly the dearomatized (4+2) cycloadducts in good yields.

Metal-Free Synthesis of 6-Phosphorylated Phenanthridines: Synthetic and Mechanistic Insights.

A novel and efficient method for the generation of phosphinoyl radicals from the combination of diphenyliodonium salt (PhI,OTf) with triethylamine (EtN) in the presence of secondary phosphine oxides is reported. By employing this practical and simple approach, a large variety of 6-phosphorylated phenanthridines have been synthesized through the addition of phosphinoyl radicals to isonitriles as radical acceptors. The reaction works smoothly in the absence of any transition metal or photocatalyst.