Kinetic Studies Prove High Catalytic Activity of a Diene–Rhodium Complex in 1,4‐Addition of Phenylboronic Acid to α,β‐Unsaturated Ketones

In the 1,4-addition of phenylboronic acid to alpha,beta-unsaturated ketones, [Rh(OH)(cod)]2 has a much higher catalytic activity than [Rh(OH)(binap)]2 (cod = 1,5-cyclooctadiene, binap = 2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl). Kinetic studies revealed that the rate-determining transmetalation step in the catalytic cycle has a large rate constant when [Rh(OH)(cod)]2 is used.