Metal-Templated Assembly of Cyclopropane-Fused Diazepanones and Diazecanones via <i>exo</i>-<i>trig</i> Nucleophilic Cyclization of Cyclopropenes with Tethered Carbamates

A strain-release-driven, cation-templated nucleophilic 7- and 8-exo-trig-cyclization of tethered Boc-protected amines to cyclopropenes is described. The featured reaction proceeds in diastereo- and regioselective fashion and allows for preparation of the corresponding 2,5-diazabicyclo[5.1.0]­octan-6-ones and 2,6-diazabicyclo[6.1.0]­nonan-7-ones as sole products in high yields. Preliminary studies on anticancer activities of these novel cyclopropane-fused medium heterocycles were performed.