121190-30-5Relevant academic research and scientific papers
Claisen rearrangement of N-silyl ketene N,O-acetals generated from allyl N-phenylimidates
Metz, Peter,Linz, Cornelia
, p. 3951 - 3966 (2007/10/02)
Deprotonation and subsequent N-silylation of allyl N-phenylimidates 1 lead to N-silyl ketene N,O-acetals 5 which undergo a Claisen rearrangement to yield γ,δ-unsaturated anilides 3 after hydrolytic work-up. The temperature for the rearrangement step is dependent on the nature of the substituent R2 in 5. Ketene acetals 5 with R2=H rearrange readily at room temperature, while heating at 130°C is required if R2≠H. The degree of simple diastereoselection attainable for the conversion of 1 to 3 is strongly affected by the size of the substituent R4. With R4>H excellent anti/syn selectivity is caused by efficient suppression of the rearrangement pathway via a boat transition state. This rationale is supported by NOE difference data obtained for several allyl N-phenylimidates and N-silyl ketene N,O-acetals.
THERMAL O -> C REARRANGEMENT OF N-PHENYL-ALLYLIMIDATES
Metz, P.,Mues, C.
, p. 6841 - 6854 (2007/10/02)
Properly substituted N-phenyl-allylimidates 1 are shown to undergo preferential O -> C sigmatropic rearrangement on heating.The diastereoselectivity of this reaction resembles the one observed in ortho ester Claisen rearrangements.
