Yoshimori Shunpei, Jin Ren-Hua
Department of Applied Chemistry, Faculty of Chemistry and Biochemistry, Kanagawa University, Yokohama, Japan.
Chirality. 2025 Feb;37(2):e70026. doi: 10.1002/chir.70026.
In this work, we report a one-pot approach that combines crystal ripening with the Suzuki-Miyaura coupling reaction. We investigated the reaction between 2-methoxyphenyl bromide and 2-methoxyphenylboronic acid, catalyzed by a series of Pd-loaded chiral optical (- or -) and racemic (-) silica/polyethyleneimine (PEI) systems, which produced crystalline 2,2'-dimethoxybiphenyl (DMB). The silica used as a catalyst was prepared using our previously established method, in which chirality was imparted to the silica through catalytic templates composed of polyethyleneimine (PEI) and tartaric acid. Both enantiopure (- or -; 100% ee) and racemic (-; 0% ee) tartaric acid-mediated silica, after tartaric acid removal and palladium (Pd) loading, exhibited similar catalytic activities, leading to the quantitative precipitation of 2,2'-dimethoxybiphenyl in a water/ethanol (1:1 by volume) medium. Interestingly, the 2,2'-dimethoxybiphenyl crystals formed and ripened in the presence of Pd-loaded chiral - and -silica/PEI exhibited octahedral morphology and displayed remarkable chiroptical activity with a mirror-image relationship. This represents a novel example of using chiral Pd-loaded silica to synthesize axially chiral biphenyl in crystalline form.
在本工作中，我们报道了一种将晶体熟化与铃木-宫浦偶联反应相结合的一锅法。我们研究了在一系列负载钯的手性光学（-或-）和外消旋（-）二氧化硅/聚乙烯亚胺（PEI）体系催化下，2-甲氧基苯基溴与2-甲氧基苯硼酸之间的反应，该反应生成了结晶性的2,2'-二甲氧基联苯（DMB）。用作催化剂的二氧化硅是采用我们先前建立的方法制备的，其中通过由聚乙烯亚胺（PEI）和酒石酸组成的催化模板将手性赋予二氧化硅。在去除酒石酸并负载钯之后，对映体纯的（-或-；100% ee）和外消旋的（-；0% ee）酒石酸介导的二氧化硅表现出相似的催化活性，导致在水/乙醇（体积比1:1）介质中定量沉淀出2,2'-二甲氧基联苯。有趣的是，在负载钯的手性-和-二氧化硅/PEI存在下形成并熟化的2,2'-二甲氧基联苯晶体呈现八面体形态，并显示出具有镜像关系的显著手性光学活性。这代表了使用负载手性钯的二氧化硅以结晶形式合成轴向手性联苯的一个新例子。
