Evaluation of TlOH Effect for Pd⁰-Mediated Cross-Coupling of Methyl Iodide and Excess Boronic Acid Ester toward Fabrication of [¹¹C]CH₃-Incorporated PET Tracer

The use of thallium(I) hydroxide (TlOH) as a base is known to extremely accelerate the Suzuki-Miyaura cross-coupling reaction using organoboronic acid or organoboronic acid ester as a substrate. Here, we investigated the effects of TlOH by comparing with other conventional bases such as KOH, K2CO3, and CsF for Pd0-mediated rapid cross-coupling reactions between CH3I and organoborane reagents, such as phenyl-, (Z)-4-benzyloxy-2-butenyl-, and benzylboronic acid pinacol esters under the conditions CH3I/borane/Pd0/base (1:40:1:3) in THF/H2O or DMF/H2O for 5 min with an aim to fabricate a PET tracer efficiently. Consequently, however, the use of TlOH was much less efficient than the other bases for the acceleration of cross-coupling reactions. Thus, it was reconfirmed that the milder and non-toxic conditions using K2CO3 or CsF so far developed by our group were most appropriate for the rapid C-methylations.

Suzuki-Miyaura反应引入本科生教学实验的探索

Suzuki-Miyaura反应是最重要的有机反应之一。探讨了如何将该反应引入到本科生的实验教学中,学生通过文献查阅预测不同反应底物的反应结果,并自行设计实验方案予以验证,从而了解Suzuki反应的特点和主要影响因素,这种研究型的教学方法不仅可以让学生掌握Schlenk技术,学会无水无氧操作,提高实验技能,拓展知识面,在较高层次上了解化学实验领域中的特殊研究方法及手段,还可以强化学生的科研素质及研究能力,对促进本科生全面能力的提高有着积极作用。