Allylic gem-diboronic esters: synthesis, reactivity, and applications in regio-, chemo-, and stereoselective C-C bond formation.

Recent advances in the synthesis and reactivity of allylic gem-diboronic esters have established these compounds as uniquely programmable nucleophiles for highly selective C-C bond formation across diverse reaction manifolds. Their dual boron functionality enables precise control over regio-, chemo-, and stereoselectivity under both metal-catalyzed and metal-free conditions. Efficient synthetic strategies have significantly expanded access to structurally diverse allylic gem-diboronic esters, while their reactivity has been broadly explored in 1,2- and 1,4-additions, nucleophilic aromatic substitution, carbon-heteroatom bond formation, and deborylative allylation-rearrangement cascades. Collectively, these advances establish allylic gem-diboronic esters as versatile and programmable synthetic platforms for the selective construction of densely functionalized and stereochemically complex molecular architectures.