Chemo‐ and Enantioselective Intramolecular Silver‐Catalyzed Aziridinations
作者:Minsoo Ju、Cale D. Weatherly、Ilia A. Guzei、Jennifer M. Schomaker
DOI:10.1002/anie.201704786
日期:2017.8.7
nitrene-transfer reactions are a powerful tool for the preparation of enantioenriched amine building blocks. Reported herein are chemo- and enantioselective silver-catalyzed aminations which transform di- and trisubstituted homoallylic carbamates into [4.1.0]-carbamate-tethered aziridines in good yields and with ee values of up to 92 %. The effects of the substrate, silver counteranion, ligand, solvent, and
(4+3) Annulation of Donor‐Acceptor Cyclopropanes and Azadienes: Highly Stereoselective Synthesis of Azepanones
作者:Stefano Nicolai、Jérôme Waser
DOI:10.1002/anie.202209006
日期:2022.9.5
Azepanones are important and widespread seven-membered heterocycles, but their synthesis is challenging. A convergent method to access these scaffolds was developed relying on a (4+3) annulation reaction of azadienes and donor-acceptor cyclopropanes. Good to excellent yields and high diastereoselectivity were achieved using Yb(OTf)3 as the catalyst. Asymmetric induction was possible with Cu(OTf)2 in