Synthesis of Dihydroindolooxazines via a Redox-Neutral, Gold-Catalyzed Hydride-Transfer Process

Redox-neutral gold-mediated processes are particularly valuable for C–H bond functionalization. When these transformations proceed stepwise via intramolecular hydride transfer to an electrophilic gold(I) center, their efficiency critically depends on the nature of the hydride donor. We report herein that, in contrast to tertiary amines, which strongly coordinate to gold and thereby tend to inhibit catalysis, benzyl ethers can serve as effective hydride donors, enabling a smooth catalytic C–H functionalization sequence. This reactivity is illustrated by the synthesis of a series of dihydroindolooxazines, obtained in moderate to high yields under mild catalytic conditions.