A complementary dual carbonyl activation strategy for the syn­thesis of polycyclic alkaloids has been developed. Successful appli­cations include the synthesis of tetracyclic alkaloids harmalanine, harmalacinine, pentacyclic indolo­quinolizidine alkaloid nortetoyobyrine, and octacyclic β‑carboline alkaloid peganumine A. The latter synthesis features a protecting‐group‐free assembly and an asymmetric disulfon­imide catalyzed cyclization. Furthermore, formal syntheses of hirsutine, deplancheine, 10‐desbromo­arborescidine A, and oxindole alkaloids rhynchophylline and isorhyncho­phylline have been achieved. Finally, a concise synthesis of berberine alkaloid ilicifoline B was completed.