6H‐1.2‐Oxazine durch 1.4‐Addition an konjugierte Diene

Abstract

Eine durch Schwermetallsalze katalysierbare 1 .CAddition von Nitrosylschwefelsaure oder Dinitrosyldisulfat an konjugierte Diene in aprotischen, dipolaren Losungsmitteln fuhrt uber den ungesattigten Nitroso-schwefelsaurehalbester und eine spontane cyclisierende Selbstalkylierung des daraus gebildeten Oxirns zum 6H-1.2-Oxazin-System. Thermische Zersetzung der 6H-1.2-Oxazine liefert Pyrrole.

Reactions of Nitrosonium Ethyl Sulfate with Olefins and Dienes: An Experimental and Theoretical Study

“…Our computational data seem to suggest that the s-cis π-complex Ia (which is in equilibrium with dihydrooxazinium cation IIIa ) is formed as an initial product of such electrophilic attack, followed by deprotonation to form oxazine 11 (or its salt 10 ). In the case when an equimolar amount of the nitrosating reagent is used, a basic workup of the reaction mixture then furnishes oxazine as the only product …”