Abstract A 12-step total synthesis of (±)-duocarmycin SA (1) was achieved from a readily available pyrrole 3 by way of 7, 10/11, 14 and 18, using a SnCl 2-mediated reaction of a singlet oxygen adduct 6 with 5, as well as the Heck and Mitsunobu reactions on 9 and 16 as key steps.