Thiazole-5-carbaldehyde Synthesis by Cascade Annulation of Enaminones and KSCN with Dess–Martin Periodinane Reagent
Kang Chen, Baoli Zhao, Yunyun Liu, Jie‐Ping Wan
Abstract
The Dess-Martin periodinane (DMP) reagent-mediated reactions of tertiary enaminones with potassium thiocyanate for the synthesis of thiazole-5-carbaldehydes are developed. The product formation involves cascade hydroxyl thiocyanation of the C═C double bond, intramolecular hydroamination of the C≡N bond, and thiazole annulation by condensation on the ketone carbonyl site, representing novel reaction pathways in the reactions between enaminones and thiocyanate salt. DMP plays dual roles in mediating the free radical thiocyanation and inducing the unconventional selective thiazole-5-carbaldehyde formation by masking the in situ generated formyl group during the reaction process.
Topics & Concepts
ChemistryThiazoleAnnulationReagentKetonePotassium thiocyanateThiocyanateOrganic chemistryCombinatorial chemistryMedicinal chemistryCatalysisCatalytic C–H Functionalization MethodsSulfur-Based Synthesis TechniquesSynthesis and Catalytic Reactions