Palladium-Catalyzed Oxidative Annulation of 1-Hydroxy-o-Carborane with Internal Alkynes:Facile Synthesis of Carborane-Fused Oxaboroles

摘要

A palladium catalyzed oxidative annulation of 1-hydroxy-o-carborane with internal alkynes via regio-selective B(3)-H bond activation has been developed for facile synthesis of a series of C,B-substituted carborane-fused oxaboroles.These molecules can undergo intramolecular oxidative dehydrogenative coupling to afford carborane-fused large π systems for potential applications in organic materials.The reaction mechanism is also proposed,involving hydroxy deprotonation,nucleopalladation of alkyne,regioselective electrophilic B—H substitution and reductive elimination.