3-Sulfolenes and Their Derivatives: Synthesis and Applications

The diverse substitution patterns available to 3-sulfolenes have long made them useful for the preparation of multi-substituted 1,3-diene equivalents. More recently, the 3-sulfolene motif itself (or its reduced sulfolane congener) is finding increasing application as a structural element in the creation of molecules for biological applications. This review describes various methods to afford 3-sulfolene building blocks and their derivatives. Selected applications in synthetic and medicinal chemistry are also discussed. 1 Introduction 2 The Preparation of Monocyclic Sulfolene Building Blocks 2.1 Sulfolenes through Electrophilic Addition 2.1.1 Sulfolenes through Nucleophilic Addition to 4-Bromo-2-sulfolene 2.2 Sulfolenes through Oxidation of a Thiol Precursor 2.3 Sulfolenes through Noble Metal Catalysis 2.4 Sulfolenes through Deprotonation Followed by Alkylation 3 Synthesis of Bicyclic Sulfolenes and Their Derivatives 3.1 Bicyclic Sulfolenes through Alkylation Chemistry 3.2 Heteroaromatic Bicyclic Sulfolenes 3.3 Bicyclic Sulfolenes through Dipolar Cycloaddition 4 The Sulfolane Function in Medicinal Chemistry 5 Conclusion