Synthesis of complex aryl MIDA boronates by Rh-catalyzed [2+2+2] cycloaddition.

A Rh-catalyzed [2+2+2] cycloaddition approach for the synthesis of BMIDA-functionalized arenes is reported. The developed method overcomes the long-standing reactivity problems associated with internal alkynes and allows access to highly functionalized borylated benzene scaffolds. The method is broadly functional group tolerant and generally high yielding. The utility of the products is demonstrated through elaboration of the BMIDA motif, and in the synthesis of fused heterocycles via intramolecular Chan-Lam etherification and amination. The dominance of sterically controlled reactivity is described.