Synthesis of dihydropyrroles from in situ-generated zwitterions via Rh2(adc)4/TBAI dual catalysis

Triggered by formation of alpha-imino carbene, the regioselective synthesis of dihydropyrroles was achieved via a cascade 1,3-sulfinate migration/annulation. The sulfinate group was converted into sulfone during the group migration, and a stable anion bearing two electron-withdrawing groups was thus formed. The addition of a catalytic amount of iodide is believed to assist the cleavage of the C-O bond, and the formation of a more stable carbocation. Thermodynamic product dihydropyrroles were produced efficiently rather than kinetic product cyclopropanes. This dual catalysis system would afford chemists a new strategy to control the annulation selectivity of zwitterions bearing multiple reactive sites and may be employed in flexible and divergent synthesis of different ring systems.

Automated summary

In this study, the regioselective synthesis of dihydropyrroles was achieved through a cascade reaction. By employing a specific catalyst, the desired product was efficiently synthesized. This method has great potential for the synthesis of compounds with different ring systems.