[4+3] annulation of diazoenals and 3-substituted 2-oxindoles: rapid access to indolo-oxazepines and a 5-HT4 receptor antagonist core

Herein, we report a new catalytic strategy for the efficient construction of indolo-oxazepine heterocycles. The transformation features a dirhodium carboxylate/Brønsted acid co-catalyzed [4+3] annulation between diazoenals and 3-substituted 2-oxindoles, providing...