Simply swapping the counteranions of TMS leads to a switchable regioselectivity in C2– and C3–H thiolation of indoles.

An unexpected time-controlled highly selective C3- or C2-sulfinylation of pyrroles with sulfinamides is reported here for the first time.

Reaction of alcohols with sodium arenesulfinates could afford either sulfones or sulfinates, and O‐attack of sulfinate anions onto the in situ generated carbocation intermediates from alcohols was the previous proposed reaction mechanism in many syntheses of sulfinates. This concept, which is often used consciously or unconsciously, was revised herein by using isotopic labeling experiments and development of an improved sulfinate synthesis. The improved sulfinate synthetic protocol possesses many advantages such as a high sulfinate/sulfone selectivity, a broad substrate scope, metal‐free, and mild reaction conditions. The revised reaction mechanism necessitates revision of many previous proposed reaction mechanisms in literatures.