Intramolecular reactions of N-nitrenes: description of the transition state geometry for addition to alkenes

Oxidation of the N-aminoquinazolones (10) and (11) generates the corresponding N-nitrenes which add intramolecularly to both double bonds. Although nitrene addition is stereospecifically cis, both faces of each double bond are attacked and consequently stereoisomers are formed. From the different selectivity of the N-nitrenes for the two double bonds in (10) and (11)[or (29)] by comparison with (15) and (24), respectively and from a consideration of the stereoisomer ratios, it is concluded that concerted addition of the N-nitrene to the double bonds in (10) and (11) obtains via a transition-state geometry resembling that shown in (34).