Allyl and propargyl sulfonium salts are readily available reagents and have recently emerged as versatile building blocks in the assembly of cyclic skeletons. As an alternative to the classical sulfonium salts, allyl and propargyl sulfonium salts can convert to the corresponding vinyl sulfur ylide or allenic sulfonium salt intermediates that contain diverse nucleophilic or electrophilic reactive positions, thereby enabling a great variety of annulation reactions. In this review, we provide a comprehensive overview of the recent developments on this growing field by summarizing the annulation reactions involving allyl and propargyl sulfonium salts.
