Herein, a mild and operationally simple method for the Suzuki−Miyaura cross-coupling of boronic esters is described. Central to this advance is the use of the organic-soluble base, potassium trimethylsilanolate, which allows for a homogeneous, anhydrous crosscoupling. The coupling proceeds at a rapid rate, often furnishing products in quantitative yield in less than 5 min. By applying this method, a >10-fold decrease in reaction time was observed for three published reactions which required >48 h to reach satisfactory conversion.

Reaction conditions have been developed for refractory heteroaryl–heteroaryl Suzuki–Miyaura cross-couplings. The reported method employs neopentyl heteroarylboronic esters as nucleophiles, heteroaryl bromides and chlorides as the electrophiles, and the soluble base potassium trimethylsilanolate (TMSOK) under anhydrous conditions. The addition of trimethyl borate enhances reaction rates by several mechanisms, including (1) solubilization of in situ-generated boronate complexes, (2) preventing catalyst poisoning by the heteroatomic units, and (3) buffering the inhibitory effect of excess TMSOK. The use of this method enables cross-coupling of diverse reaction partners including a broad range of π-rich and π-deficient heteroaryl boronic esters and heteroaryl bromides. Reactions proceed in good yields and short reaction times (3 h or less).