N-Aminonitrene

N- Amino- and N-substituted amino-pyrroles readily undergo Diels-Alder additions and add to activated alkynes at room temperature. The resulting azanorbornadienes extrude N-aminonitrenes and this forms the basis of an unusual synthesis of benzene derivatives (81S753,81TL3347). It has been found that ethyl/3-phenylsulfonylpropiolate (135) is a superior dienophile to DMAD (Scheme 50). 

N- Aminopyrroles undergo Diels-Alder addition with alkynes bearing electron-withdrawing groups. Loss of N- aminonitrene from the resulting adducts yields benzenoid derivatives (Scheme 68) (81TL1767) (see also Section 3.02.2.10). 

It should be noted that -aminotetrachlorophenylnitrene is a phenylene analogue of the diazene (aminonitrene) NHj—N- <-> NH2=N . Furthermore, 1,1 -diazenes are known to protonate to give relatively stable cations (R N—NH- ) (Lemal, 1970). 

The reaction proceeds by an intermediate of the aminonitrene type, which leads, in parallel to 3,4-diazabicyclo[4.3.0]non-2-ene, to the formation of N,N -azo-3-azabicyclo[3.3.0]-octane [2]. 

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