Unexpected Formation of Triphenylborane from Phenylboronic Acid and Its Use as an Intermediate in Palladium‐Catalyzed Cross Coupling Reaction

Abstract

Triphenylborane was unexpectedly formed from phenylboronic acid in the presence of an inorganic base and a polar solvent. When K2CO3 was used as the base and DMF was used as the solvent, 0.22 mmol of triphenylborane was obtained from 1.5 mmol of phenylboronic acid after 1 h at 130 °C. The in‐situ formed triphenylborane reacted with chorobenzene over a supported Pd catalyst to afford biphenyl as the cross coupling product.

Latest Developments on Palladium- and Nickel-Catalyzed Cross-Couplings Using Aryl Chlorides: Suzuki–Miyaura and Buchwald–Hartwig Reactions

“…Motokura et al observed the unexpected formation of triphenylborane (Ph 3 B) during a palladium-catalyzed SM coupling reaction using a mesoporous silica-supported Pd complex catalyst Pd/MS. 44 Ph 3 B is an active intermediate in the SM coupling of aryl chlorides and phenylboronic acids. Meanwhile, Bai et al reported an effective photothermal dual-responsive Pd 1 Cu 4 /Ce x O y catalyst (1 mg/mmol substrate).…”

“…Motokura et al observed the unexpected formation of triphenylborane (Ph 3 B) during a palladium-catalyzed SM coupling reaction using a mesoporous silica-supported Pd complex catalyst Pd/MS. 44 45 The SM reactions of aryl chlorides and arylboronic acids with this catalyst proceeded under thermal heating at 70 °C. Additionally, SM cross-coupling proceeded under visible-light irradiation at room temperature to afford biaryls in up to 99% yield.…”

“…Motokura et al observed an unexpected formation of triphenyl borane (Ph3B) during a palladiumcatalyzed SM coupling reaction 44. They used mesoporous silicasupported Pd complex catalyst Pd/MS.…”