Synthesis of β,β-Dithioketones by Merging C–C and C–S Bond Cleavage in 1 + 1 + 1 + 1 + 1 + 1 Annulation

An unconventional 1 + 1 + 1 + 1 + 1 + 1 annulation process was developed for the construction of β,β-dithioketones by merging C–C and C–S bond cleavage. In this reaction, rongalite concurrently served as triple C1 units, dual sulfur(II) synthons, and a reductant for the first time. Mechanism investigation indicated that the reaction involved the self-mediated valence state change of rongalite. By performing this step-economical method, the challenging construction of C5-substituted 1,3-dithiane can be achieved under mild and simple conditions.