Synthesis of Highly Functionalized 12-Membered Trifluoromethyl Heterocycles via a Nondecarboxylative Pd-Catalyzed [6 + 6] Annulation

An
efficient method for the construction of 12-membered heterocycles
with a trifluoromethyl group (3) was achieved via a nondecarboxylative
Pd-catalyzed [6 + 6] annulation of six-membered trifluoromethyl benzo­[d]­[1,3]­oxazinones (1) with four-membered vinyl
oxetanes (2). A variety of relatively large heterocycles 3 featuring a stereogenic trifluoromethylated carbon center,
an amino group, as well as an alkenyl and a carbonate moiety were
obtained. An X-ray crystallographic analysis revealed a unique 3D
architecture of the products that affords an attractive chemical space.
Whereas the method can be applicable for nonfluorinated substrates,
the trifluoromethyl group plays a vital role in this unexpected Pd-catalyzed
nondecarboxylative ring expansion.