The Amino- and Aza-Cope Rearrangements

3-Amino group in the 1,5-diene system also accelerates the Cope rearrangement. This version of the Cope rearrangement is known as the amino-Cope rearrangement. The products of the reactions are useful in the synthesis of unsaturated aldehydes. The following examples are illustrative [59, 60]  

The aza-Cope rearrangement of cyclopentane derivative 86 gives a bicyclic pyrrolidine 87 in which original ring is expanded by one carbon atom [63]. 

When cyclic ketone was used to generate an iminium ion, the yield of the reaction becomes low due to unfavorable steric strain in chair-like TS for example, the 

The rearrangements of 4-hydroxy-2-aza-1,5-dienes 89 to 89a in anionic forms are known as the anionic -oxy-2-aza-Cope rearrangements [65]. 

The Cope rearrangements of 1-aza-1,5-dienes are known as the 1-aza Cope rearrangements (1-ACR). For example, N-acylimine 90 obtained from flash vacuum pyrolysis (FVP) of N-acyl hydroxylamine derivative gives pyridine derivative 91 by 1-ACR [66]. 

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