Cyclopropane-Fused -Heterocycles via Aza-Heck-Triggered C(sp)-H Functionalization Cascades.

Unique examples of aza-Heck-based C(sp)-H functionalization cascades are described. Under Pd(0)-catalyzed conditions, the aza-Heck-type cyclization of -(pentafluorobenzoyloxy)carbamates generates alkyl-Pd(II) intermediates that effect C(sp)-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.