Cyclopropane-Fused N‑Heterocycles via Aza-Heck-Triggered C(sp³)–H Functionalization Cascades

Unique examples of aza-Heck-based C­(sp³)–H functionalization cascades are described. Under Pd(0)-catalyzed conditions, the aza-Heck-type cyclization of N-(pentafluorobenzoyloxy)­carbamates generates alkyl–Pd­(II) intermediates that effect C­(sp³)–H palladation en route to cyclopropanes. Key factors that control the site selectivity of the cyclopropanation process have been elucidated such that selective access to a wide range of ring- or spiro-fused systems can be achieved.