ADDITION D'AROYL-2 AZIRIDINES, YLURES D'AZOMETHINE POTENTIELS, AUX ISOCYANATE ET ISOTHIOCYANATE DE PHENYLE.

Article abstract of DOI:10.1016/S0040-4020(01)85891-9

The cycloaddition of azomethine ylids, generated from the thermal ring opening of aroylaziridines, occurs at the CN double bond of phenylisocyanate in accordance with previous work in the area.The literature claimed a different behaviour with phenylisothiocyanate.We have shown that the author's assumptions are based on incorrect structure determination of the products.The addition occurs also on the CN double bond of phenylisothiocyanate and the evolution of the primary adduct (i.e. a thioimidazolidone) is explained by the formation of a biradical stabilized through a capto-dative effect.This biradical cyclises to the transient 1,3 thiazolidine 12A.