摘要:
The anionic rearrangement of N,N'-dimethyl-N,N'-diacylhydrazines to 1,2-disubstituted succinamides proceeds in the presence of a ajacent enolate-stabilizing substituent such as a phenyl group. However, a substituent that poorly stabilizes the alpha-carbanion results in an extremely-low yield of the products. The [3,3] sigmatropic rearrangement generally requires a chair form for the cyclic six-centered transition state. When the dienolates of N,N'-diacylhydrazines have favorable steric factors for the cyclic transition state, the rearrangement seems to proceed smoothly. The diacylates of 5- to 8-membered cyclic hydrazine which readily adopt a favorable conformation for the:[33] :rearrangement readily rearrange to 9- to 12-membered cyclic diamides.