Synthesis of Cinchona Alkaloid-Derived Chiral Polymers by Mizoroki-Heck Polymerization and Their Application to Asymmetric Catalysis
Synthesis of Cinchona Alkaloid-Derived Chiral Polymers by Mizoroki-Heck Polymerization and Their Application to Asymmetric Catalysis
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DOI：
10.1021/ma5001018
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发表时间：
2014-03-25
期刊：
影响因子：
5.5
通讯作者：
Itsuno, Shinichi
中科院分区：
文献类型：
--
作者：
Parvez, Md Masud;Haraguchi, Naoki;Itsuno, Shinichi
为了促进不对称催化过程，我们设计了新型聚合物手性催化剂。由于金鸡纳生物碱衍生物的季铵盐在各种不对称转化中表现出高效的催化活性，我们合成了在聚合物主链上含有金鸡纳啶基团的新型手性聚合物催化剂。金鸡纳生物碱衍生二聚体和二碘化物之间的反复Mizoroki-Heck偶联反应产生手性聚合物催化剂，随后将其用作不对称苄基化反应的催化剂，以更高的产率和对映选择性得到相应的苯丙氨酸衍生物。由于聚合物催化剂的不溶性，它们很容易从反应混合物中回收并重复使用。
To facilitate the asymmetric catalysis process, we designed novel polymeric chiral catalysts. Since quaternary ammonium salts of cinchona alkaloid derivatives show efficient catalytic activity in various asymmetric transformations, we have synthesized novel chiral polymer catalysts containing cinchonidinium moieties in the main chain of the polymer. Repetitive Mizoroki-Heck coupling reactions between the cinchona alkaloid-derived dimer and diiodide afforded the chiral polymer catalysts, which were subsequently used as catalysts in asymmetric benzylation reactions to yield the corresponding phenylalanine derivatives in higher yields and levels of enantioselectivity than can be obtained with a monomeric catalyst. Because of the insolubility of the polymeric catalysts, they were easily recovered from the reaction mixture and reused several times.