Ethyl azodiformate

Ethyl azodiformate is a well-known and useful dienophile in the Diels-Alder reaction.8 /-Butyl azodiformate behaves ami-... 

In the photolysis of neat ethyl azidoformate (66) diethyl azodiformate (76) is produced in the early stages of the process, to be later replaced by the triethyl nitrilotriformate (77) which is produced in 58% yield A detailed investigation showed that the nitrilo compound (77) is apparently not formed by the action of a nitrene, and the reaction between an azide and an excited azodiformate was suggested as a possible pathway. Hancock has proposed an alternative mechanism which involves triazacyclopropene (see, however, Huisgen ). 

The infrared spectrum of ethyl and /z-propyl azodiformates have high frequency carbonyls near 1775 cm due to the electron withdrawing character of the N=N bond. Strong bands involving the C—O bonds appear near 1260-1220 and 1060-1020 cm" As seen in Fig. 11.2, the N=N stretching frequency is 1555 cm" in the Raman effect. 

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