Thermal Ring Expansion of 2-Sulfonylimidoyl-1-phthalimidoaziridines into <i>N</i>
-Sulfonylimidazoles
作者:Aleksandr Stukalov、Vitalii V. Suslonov、Mikhail A. Kuznetsov
DOI:10.1002/ejoc.201701806
日期:2018.4.17
Di‐, tri‐substituted, and spiro‐fused 2‐sulfonylimidoyl‐1‐phthalimidoaziridines are transformed to di‐, tri‐substituted, and condensed N‐sulfonylimidazoles upon thermolysis. This ringexpansion is accompanied by an intramolecular 1,3‐sulfonyl shift.
Asymmetric Conjugate Addition of Malonate Esters to α,β-Unsaturated<i>N</i>-Sulfonyl Imines: An Expeditious Route to Chiral δ-Aminoesters and Piperidones
作者:Miguel Espinosa、Gonzalo Blay、Luz Cardona、José R. Pedro
DOI:10.1002/chem.201302687
日期:2013.10.25
The asymmetric conjugate addition of malonate esters to α,β‐unsaturated N‐sulfonyl imines is catalyzed by PyBOX/La(OTf)3 complexes in the presence of 4 Å MS. The reaction gives the corresponding E enamines bearing a stereogenic center at the allylic position with good yields and enantiomeric ratios up to 97:3. This reaction provides a synthetic entry to chiral δ‐aminoesters and piperidones.
By employing copper dibromide as a catalyst, Michael addition–condensation of 3‐substitutedindoles with α,β‐unsaturated ketimines was realized. The reactions afforded a large variety of 9H‐pyrrolo[1,2‐α]indoles with good yields (up to 99 %). In addition, a plausible reaction mechanism was proposed.