A highly efficient Pd(OAc)2/guanidine aqueous system for the room temperature Suzuki cross-couplingreaction has been developed. The new water-soluble and air-stable catalyst Pd(OAc)2a(1f)2 from Pd-(OAc)2 and 1,1,3,3-tetramethyl-2-n-butylguanidine (1f) was synthesized and characterized by X-raycrystallography. In the presence of Pd(OAc)2a(1f)2, coupling of arylboronic acids with a wide range ofaryl halides, including aryl iodides, aryl bromides, even activated aryl chlorides, was carried out smoothlyin aqueous solvent to afford the cross-coupling products in good to excellent yields and high turnovernumbers (TONs) (TONs up to 850 000 for the reaction of 1-iodo-4-nitrobenzene and phenylboronic acid).
Furthermore, this mild protocol could tolerate a broad range of functional groups.
