Construction of Oxadiazepines via Lewis Acid-Catalyzed Tandem 1,5-Hydride Shift/Cyclization

Expeditious access to oxadiazepines
via 1,5-hydride shift/cyclization
of pyrrolidine- or tetrahydroisoquinoline-containing nitrones has
been developed. With 1,3-dipole nitrones serving as the hydride acceptors,
this transformation was promoted by a Lewis acid, providing access
to structurally diverse oxadiazepines in good yields. A one-pot process
for in situ nitrone formation, a 1,5-hydride shift, and ring cyclization
was also realized.