Transition-metal-free synthesis of vicinal triborated compounds and selective functionalisation of the internal C-B bond.

1,2,3-Triborated compounds can be prepared by simple nucleophilic borylation of 1,3-dienes, without the assistance of metal catalysts. Selective functionalisation of the internal C-B bond of the 1,2,3-triborated compounds, through cross-coupling with aryl iodides, highlights the powerful methodology toward polyfunctionalisation.