ADDITION DE CYANO-2 AZIRIDINES, YLURES D'AZOMETHINE POTENTIELS AUX ISOCYANATES

Article abstract of DOI:10.1016/S0040-4020(01)90608-8

The addition of azomethine ylids resulting from the thermal ring opening of the corresponding 2-cyanoaziridines on methyl and phenyl isocyanates occured exclusively at the C=N double bond.Only one orientation of the addition was observed and a mixture of diastereoisomeric imidazolidones was obtained in each case.On the basis of X ray structure of one diastereoisomer the stereochemistry of the other imidazolidones was established by NMR considering the long range coupling constants values between H₂ and H₅ (J_cis < J_trans).The reaction of sodium methylate with the imidazolones led to imidates resulting from a nucleophilic addition on the nitrile function on the C₂ carbon atom of the heterocycles.These imidates are easily hydrolyzed to the corresponding esters.If the reaction was carried out in the presence of oxygen the CHCN group was transformed into C=O group via the oxidation of the C₂ carbanion.