Rearrangement ammonium enolate Claisen

Discussing the stereochemical outcome of the Claisen rearrangements, two aspects had to be considered. On one hand, the relative configuration of the new stereogenic centers was found to be exclusively syn in 308 and 309 suggesting a chair-like transition state c-a and c-fS, respectively, including a Z acyl ammonium enolate structure (complete simple diastereoselectivity/internal asymmetric induction, Scheme 10.64). 

The third mechanism starts with addition of the AT-allylamine 103 to the cumulated acceptor system of an allene carbonester 108 (Acc=CHC02Me) to form an intermediate iV-allyl ammonium amide enolate 109 (allene carbonester Claisen rearrangement). The anion stabilizing group is exclusively placed... 

Allyl ethers of enols and phenols undergo rearrangement to C-allyl derivatives when heated to sufficiently high temperatures. The reaction, named after its discoverer (Claisen, 1912), was first observed when ethyl O-allylacetoacetate was subjected to distillation at atmospheric pressure in the presence of ammonium chloride.1 2... 

Nucleophiles like lithium enolates and organocuprates can be added to the terminus of the allyl ligand of cationic cyclic allyl(carbene)iron complexes to give 4-substituted tricarbonyl[l,(3 )-diene]iron complexes. Subsequent to the nucleophilic addition, a ferra-Claisen rearrangement is supposed to be involved in the reaction mechanism. The free dienes can be released by treatment with ceric ammonium nitrate or alkaline hydrogen peroxide (Scheme 4-65). ... 

---