Cesium‐Fluoride‐Promoted Synthesis of Stable Organocesium Reagents and Their Ambident Reactivities with Arynes

Described are the diverse reactivities of novel, stable, ambident thio‐organocesium reagents (bearing electron withdrawing groups) against benzynes. Reactions at reflux temperature predominantly led to the generation of various functionalized stable sulfonium ylides and at 40 °C the same reaction underwent direct c‐arylation. Furthermore, lack of internal hydrogen on the cesium reagent helped to produce different ortho‐bifunctional arynes in both the reactions. Interestingly, depending on the reactivities of substrates, the one‐pot tri‐component procedure generated either ylides or σ‐bond insertion products. Different structurally unique thio‐organocesium compounds have been synthesized through a mild, one‐step reaction employing CsF as a cheap source of cesium. This article also highlights the importance of their ambident character to control the divergent synthesis of stable sulfonium ylides and c‐arylation products. Furthermore, fine tuning of these substrates (lacking α‐CH protons) helped in the preparation of various ortho‐bifunctional arenes. As an advantage, reactions in one pot helped to promote the reactions through insertion mechanism to ortho‐functional arenes.