An Improved Preparation of Arylboronates:  Application in One-Pot Suzuki Biaryl Synthesis^†

Abstract

We have developed a modification of the Miyaura arylboronate synthesis(1a) by substituting a ligandless palladium catalyst for PdCl(2)(dppf). Palladium acetate, free of ligand, was found highly effective for such coupling reactions. This modified procedure is advantageous over the original Miyaura synthesis in ease of workup, catalyst removal, and low catalyst cost. Furthermore, the boronates formed in this manner can be used directly for Suzuki coupling reactions in a one-pot fashion. The biaryl products have improved impurity profiles and reduced heavy metal contamination.

Preparation of 1,3-dienyl organotrifluoroborates and their Diels–Alder/cross-coupling reactions

“…In a second attempt to overcome this problem, a diboryl reagent (49) was employed with ligandless palladium catalyst conditions, similar to the approach taken by Zhang and co-workers in their arylboronate synthesis. 52 But in this case, a homocoupled dimer (50) of the diene with was obtained. by quenching with aq.…”

Synthesis of Thienopyrimidine Derivatives Starting From Thiophene Ring and Pyrimidine Ring

“…48 The Suzuki cross-coupling reaction of compound 124 with commercially available boronic acid derivatives gave 4-aryl-2-aminopyrimidines. 49 Saponification of the ethyl ester (126) gave the corresponding acid 127, which was coupled with ethylamine hydrochloride in the presence of HATU to give ethyl amide (128) in 72 % yield (Scheme 36).…”

Microwave-assisted synthesis of 5-arylbenzofuran-2-carboxylates via Suzuki coupling using 2-quinolinealdoxime-Pd(II)-complex

“…The structures were solved by direct methods with SHELXS-97, refined using full-matrix least-squares routines against F 2 with SHELXL-97, 48 and visualized using X-SEED. 49 All non-hydrogen atoms were refined anisotropically. Disordered lattice solvent was apparent, which could not be modeled, requiring the use of SQUEEZE to remove its contribution.…”