Acortatarins A (1) and B (2), two novel spiroalkaloids with a naturally unusual morpholine motif, were isolated from the rhizome of Acorus tatarinowii. Their structures with absolute configuration were determined by spectroscopic methods, X-ray diffraction analysis, and Mosher's method. Importantly, compound 1 could significantly inhibit reactive oxygen species production in high-glucose-stimulated mesangial cells in a dose- and time-dependent manner.

An unprecedented copper-catalyzed intramolecular radical cyclization was developed for the synthesis of 3-hydroxypyrroloindoline skeletons in excellent yields. The 3-hydroxyl group was introduced by trapping the radical intermediate with molecular oxygen or TEMPO. This process represents a unique radical oxidation pathway for tryptamine/tryptophan derivatives and allows a rapid biomimetic synthesis of natural product protubonine A.