4-Azido-2-pyrrolinones

Evidence has been provided604 for intramolecular nucleophilic catalysis by the carbonyl group during methanolysis of o- and / -formylbenzenesulfonates in basic media (see Scheme 121). A theoretical study of the zwittazido cleavage of 4-azido-2-pyrrolinones has been undertaken,605 and ab initio calculations have been carried out to examine the possibility of the existence of a hexacoordinate phosphorus intermediate (469) in the migration reaction (468) —> (470) of dimethyloxyphosphorylthreonine.606... 

The photoreactions of azides can in most cases be rationalized in terms of intermediate nitrenes. Irradiation of t-butyl azide (106) in nitrogen matrices at 12 K gave the imine (107), but no evidence was obtained for a nitrene intermediate.Photoelimination of nitrogen from 4-azido-2-pyrolinones provides a new synthetic route in high yield to 3-cyano-2-azetidines, as shown, for example, for the pyrrolinone (108) in Scheme 12. ° Zwitterionic intermediates have been... 

Finally, thermolysis or photolysis of pyrrolinones bearing an azido group produces mono- or bi-cyclic j8-lactams depending upon the substituents i.e. 81 - 82 83 - 84). This new synthetic method does have its limitations in that although it is general in the monocyclic case, it does not work where n = 0 in (83), leading instead to open-chain products. 

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