Ring‐Opening 1‐Amino‐3‐aminomethylation of Donor–Acceptor Cyclopropanes via 1,3‐Diazepanes

The first ring-opening reaction of donor-acceptor cyclopropanes to give diamines is reported. For this reaction, a 1,3-bisfunctionalization was developed using cyclopropanes, triazinanes, and Sc(OTf)3 as the catalyst, followed by treatment with acid. The reaction proceeds under very mild conditions and tolerates many functional groups. Moreover, a library of various 1,3-diazepanes, which arise as intermediates of the first formal aza-[4+3]-cycloaddition reaction with donor-acceptor cyclopropanes, was synthesized.