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.
Dihydropyridones: Catalytic Asymmetric Synthesis, N- to C-Sulfonyl Transfer, and Derivatizations
作者:Carmen Simal、Tomas Lebl、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/anie.201109061
日期:2012.4.10
promotes the reaction of ammonium enolates derived from arylacetic acids with N‐tosyl‐α,β‐unsaturated ketimines, thus giving dihydropyridones with high diastereo‐ and enantiocontrol (see scheme). These products readily undergo N‐ to C‐sulfonyl photoisomerization and are derivatized to afford stereodefined piperidines and tetrahydropyrans.
NHC-Mediated Stetter-Aldol and Imino-Stetter-Aldol Domino Cyclization to Naphthalen-1(2<i>H</i>)-ones and Isoquinolines
作者:Debabrata Barman、Tanmoy Ghosh、Krishanu Show、Sudipto Debnath、Tapas Ghosh、Dilip K. Maiti
DOI:10.1021/acs.orglett.1c00337
日期:2021.3.19
N-Heterocyclic carbene-catalyzed tandem Stetter-aldol reaction of phthalaldehyde and α,β-unsaturated ketimines has been developed to afford functionalized naphthalen-1(2H)-one derivatives as the formal [4+2] annulation product. Interestingly, the reaction of aldimines led to the formation of isoquinoline derivatives instead of the expected indanone derivatives as a [4+1] annulation product.