Burke boronates

Burke boronates can serve as B-protected haloboronic acids for a wide variety of applications in iterative cross-coupling.^1–6 The corresponding boronic acids can be liberated using mild aqueous bases such as NaOH or NaHCO3.^1–4 Burke boronates are also compatible with many synthetic reagents, enabling the synthesis of complex boronic acids from simple B-containing starting materials.^3,6 They can also serve as stable building blocks for cross-coupling, i.e., under aqueous basic conditions, the corresponding boronic acid is released and coupled in situ.^2,3,7 Moreover, Burke boronates are highly crystalline, monomeric, free-flowing solids that are indefinitely stable to benchtop storage under air and compatible with silica gel chromatography.^1–3,6