Intramolecular Tsuji-Trost-type Allylation of Carboxylic Acids: Asymmetric Synthesis of Highly π-Allyl Donative Lactones.
Intramolecular Tsuji-Trost-type Allylation of Carboxylic Acids: Asymmetric Synthesis of Highly π-Allyl Donative Lactones.
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DOI：
10.1021/jacs.5b05786
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发表时间：
2015-07
影响因子：
15
通讯作者：
Yusuke Suzuki;T. Seki;Shinji Tanaka;M. Kitamura
中科院分区：
文献类型：
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作者：
Yusuke Suzuki;T. Seki;Shinji Tanaka;M. Kitamura
通过使用带有轴向手性吡啶甲酸型配体（Cl-Naph-PyCOOH：naph = 萘基，py = 吡啶）的阳离子 CpRu 络合物，实现了羧酸的 Tsuji-Trost 型不对称烯丙基化。羧酸和烯丙醇通过释放水而进行分子内缩合，而无需亲核试剂或亲电试剂部分的化学计量活化，从而获得高原子经济性和步骤经济性以及低E因子。这一成功可归因于软Ru/硬Brønstead酸联合催化中烯丙醇比烯丙酯产物具有更高的反应活性，与传统的Pd催化体系不同，它可以在微酸性条件下发挥作用。使用对映体富集的 D 标记底物对反应的立体化学结果进行详细分析，提供了对映体选择的有趣观点。
Tsuji-Trost-type asymmetric allylation of carboxylic acids has been realized by using a cationic CpRu complex with an axially chiral picolinic acid-type ligand (Cl-Naph-PyCOOH: naph = naphthyl, py = pyridine). The carboxylic acid and allylic alcohol intramolecularly condense by the liberation of water without stoichiometric activation of either nucleophile or electrophile part, thereby attaining high atom- and step-economy, and low E factor. This success can be ascribed to the higher reactivity of allylic alcohols as compared with the allyl ester products in soft Ru/hard Brønstead acid combined catalysis, which can function under slightly acidic conditions unlike the traditional Pd-catalyzed system. Detailed analysis of the stereochemical outcome of the reaction using an enantiomerically enriched D-labeled substrate provides an intriguing view of enantioselection.