Dimethyl sulfoxide participant iron-mediated cascade oxidation/α-formylation reaction of substituted 2,3-dihydropyrroles under air and protonic acid free condition.

An efficient and Brønsted acid free one-pot protocol to directly generate structurally sophisticated α-formylpyrrole derivatives in moderate to good yields has been demonstrated, involving an iron-mediated domino oxidation/formylation reaction of readily available 2,3-dihydro-1H-pyrroles in dimethyl sulfoxide and air atmosphere, in which dimethyl sulfoxide acts as the formyl donor. A possible mechanism is presented.