<scp>Palladium‐Catalyzed</scp> Oxidative Annulation of <scp>1‐Hydroxy‐<i>o</i>‐Carborane</scp> with Internal Alkynes: Facile Synthesis of <scp>Carborane‐Fused</scp> Oxaboroles^†

Abstract

Summary of main observation and conclusion A palladium catalyzed oxidative annulation of 1‐hydroxy‐ o ‐carborane with internal alkynes via regioselective 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.