C-labeled carbon into the scaffold. We highlighted the practical applicability of this method through a concise four-step total synthesis of quebrachamine, a complex monoterpene indole alkaloid. Experimental studies and density functional theory (DFT) calculations revealed a reaction pathway involving cascade 2+2 cycloaddition, retro-2+2 ring opening, decarbonylation, and cyclization, elucidating the sequence at an atomic level.
Zhang et al. (2026) studied this question.