<i>N</i>-Isocyaniminotriphenylphosphorane (Ph₃PNNC) as a metal-free catalyst for the synthesis of functionalized isoindoline-1-ones

<p>A novel application in the field of <i>N</i>-isocyaniminotriphenylphosphorane (Ph₃PNNC) chemistry has been introduced in this work. A series of substituted isoindolin-1-one ring systems has been successfully synthesized through a novel and efficient multicomponent reaction of methyl 2-formylbenzoate and primary amines in the presence of <i>N</i>-isocyaniminotriphenylphosphorane (Ph₃PNNC) as a catalyst. This one-pot three component reaction (3-CR) gives high yield using <i>N</i>-isocyaniminotriphenylphosphorane (Ph₃PNNC) as a metal-free catalyst under mild conditions.</p

The reaction of <i>N</i>-isocyaniminotriphenylphosphorane (NICITPP) with some of cyclic ketones and a primary amine in the presence of 3-phenyl-2-propynoic acid

<p>The 1:1 imine intermediate generated by the addition of a primary amine to a cyclic ketone is trapped by <i>N</i>-isocyaniminotriphenylphosphorane in the presence of 3-phenyl-2-propynoic acid and the corresponding iminophosphorane intermediate was formed. Disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular <i>aza</i>-Wittig reaction of the iminophosphorane intermediate. The reactions were completed in neutral conditions at room temperature (18–26°C). The disubstituted 1,3,4-oxadiazole derivatives were produced in excellent yields.</p

Three-component reaction of <i>N</i>-isocyaniminotriphenylphosphorane (Ph₃PNNC), biacetyl, and a carboxylic acid in water

<p>Reaction of <i>N</i>-isocyaniminotriphenylphosphorane with biacetyl in the presence of a carboxylic acid in water proceeds smoothly at RT (20–26°C) and neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in high yields. The reaction proceeds smoothly and clearly under mild conditions and no side reactions were observed.</p