Oxidation of reserpine (1) usually leads to the anhydronium bases, 3,4-dehydroreserpine (2) and 3,4,5,6-tetradehydroreserpine (3), products of overall dehydrogenation. Indoles characteristically undergo autoxidation to produce primarily allylic indolenine hydroperoxides, which are susceptible to subsequent reactions by which other oxidation products are formed. The autoxidation of indole alkaloids has not been thoroughly examined. This work describes the characterization of the hitherto unreported major product of reserpine autoxidation, 6, formed in association with a minor proportion of the expected indolenine hydroperoxide, 5. Some evidence is advanced in support of a proposed mechanism of formation of these products. © 1990, American Chemical Society. All rights reserved.