Stereospecific 1,3-Aminobromination of Donor-Acceptor Cyclopropanes.

Sn(OTf) -catalyzed 1,3-aminobromination of donor-acceptor cyclopropanes with various sulfonyl amides or electron-poor anilines and N-bromosuccinimide is reported. These experimentally straightforward reactions occurred with complete regio- and stereospecificity (for anilines) to give γ-aminated α-brominated malonic diesters in good to excellent yields (up to 98 %). These compounds served as valuable substrates for subsequent reactions to provide substituted azetidines and γ-lactams in high yields.