10.1007/s11172-008-0326-y
This research investigates the use of carborane-containing phosphorus derivatives as ligands in Pd-catalyzed cross-coupling reactions, specifically the Suzuki-Miyaura reaction, which forms carbon-carbon bonds by coupling aryl halides with boronic acids. The purpose is to develop ligands with optimized steric and electronic properties to enhance catalytic activity. The study synthesized various phosphine and phosphite ligands with different substituents and tested their efficiency in the cross-coupling reactions. Key chemicals used include phenylboronic acid, aryl halides like bromobenzene and 4-bromotoluene, and various carborane-containing ligands. The results showed that ligands with electron-withdrawing carboranyl substituents and sterically congested phosphorus centers provided the highest conversion rates. Additionally, anhydrous reaction conditions enabled the use of more synthetically accessible phosphite ligands. The findings suggest that fine-tuning the electronic and steric properties of carborane ligands can significantly improve their performance in cross-coupling reactions, opening new avenues for developing more active catalysts.
10.1021/ol900943b
This study presents a novel method for the synthesis of 1,5-benzothiazepine dipeptide mimetics using two cuprous iodide-catalyzed cross-coupling reactions. The process begins with the coupling of 4-methylphenyl bromide with amino acids under cuprous iodide catalysis to form N-aryl amino acids. This is then converted to a linear dipeptide by iodination and condensation with an acyl chloride derived from L-cysteine. The final cyclization step is achieved by a cuprous iodide/N,N-dimethylglycine-catalyzed intramolecular coupling of the aryl iodide with the released thiol to afford the 1,5-benzothiazepine dipeptide mimetic. This study also explores the use of benzoyl as an ester protecting group, which can be cleaved to obtain the desired mimetic acid form. This method can introduce a variety of N-substituents by changing the amino acid coupling partner, enabling the development of more diverse peptide mimetics for biological studies.