Synthesis and Structural Study of Iodonium Ylides Derived From 2‐Iodosylbenzenesulfonic Acid: Reagents for Preparation of Annulated Thiazoles

Novel ylidic compounds of two different types have been prepared by the reaction of 2‐iodosylbenzenesulfonic acid with the corresponding 1,3‐cyclohexanediones under acidic or basic conditions. According to X‐ray crystallographic study, these compounds have a typical for iodonium ylide structure with two carbon atoms bonding to the iodine atom with the CIC angles ranging from 94.18° to 97.25° and the IC bond distances about 2.08 (I–C alkyl ) and 2.13 Å (I–C aryl ). Numerous inter‐ and intramolecular halogen bonding interactions were observed and analyzed. In contrast to the known dimedone‐derived phenyliodonium ylides, these new iodonium ylides are generally stable compounds with high decomposition temperatures and stable for handling and storage at room temperature. The new iodonium ylides are useful reagents for the preparation of annulated thiazoles by cycloaddition reaction with thiourea.