New Electrosynthesis of Arylboronic Esters from Aromatic Halides and Pinacolborane

Abstract

A novel synthesis of arylboronic esters by a reductive electrochemical coupling reaction between aromatic halides and pinacolborane (HBpin, pin pinacolate) has been carried out leading to arylboronic esters in moderate to good yields.

The one-electron cleavage and reductive homo-coupling of alkyl bromides at silver–palladium cathodes

“…In particular, results in DMF containing TBABF 4 do confirm the one-electron character of the global cathodic process. Most reductions achieved at quite moderate potentials ranging from À1.2 V to À1.4 V vs. SCE are somewhat similar to the data already reported [10][11][12][13] at palladium cathodes (case of primary alkyl iodides) and at copper-palladium electrodes (case of primary alkyl bromides) [20]. They underline the peculiar role of palladium in the cleavage of carbon-halogen bonds.…”

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

“…731,732 Analogous to the allyl halide borylation reaction discussed in the preceding section, borylation of aryl halides can be accomplished through cathodic reduction of aryl halides in the presence of a boron electrophile. Pinacol borane 634,702 and trialkyl borates 701,703 have both been employed for such transformations. The use of the former allows the preparation of potassium trifluoroborates in one pot (Figure 43A).…”

A facile and green synthetic route to boronic acidesters utilizing mechanochemistry

“…Magnesium or aluminum anodes in combination with nickel foam or stainless steel cathodes were used and the boronic acid esters were obtained in varying yields (19-79%). 20 Inert techniques have to be applied and the reaction was carried out in dry THF, requiring 3 equiv. of HBpin.…”