“…Because sultones are synthetically very useful heterocycles in organic synthesis, many groups are currently working on sultone chemistry. − Most of the earlier procedures for sultone synthesis involved either carbanion-mediated sulfonate intermolecular or intramolecular coupling reactions (CSIC reactions) or sulfonation of olefins with dioxane–sulfur trioxide. Recently, many powerful methodologies have been developed for the synthesis of the sultones, such as intramolecular Diels–Alder reactions, ring-closing metathesis, Pd-catalyzed intramolecular coupling reactions, Rh-catalyzed C–H insertion, Rh-catalyzed carbene cyclization cycloaddition cascade reactions, etc.…”