Lewis Acid‐Mediated Decarboxylative Allylation of Enol Carbonates
Lewis Acid‐Mediated Decarboxylative Allylation of Enol Carbonates
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DOI：
10.1002/hlca.202100065
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发表时间：
2021-06
影响因子：
1.8
通讯作者：
Yoichi Dokai;T. Nishizawa;Kodai Saito;T. Yamada
中科院分区：
文献类型：
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作者：
Yoichi Dokai;T. Nishizawa;Kodai Saito;T. Yamada
高烯丙基酮可以通过各种合成反应进行转化和官能化，因此被认为是有机化学中具有代表性的结构单元之一。本工作开发了获得高烯丙基酮的另一种途径，即通过将二氧化碳固定到炔丙醇上制备的环状烯醇碳酸酯的路易斯酸介导的脱羧烯丙基化。在烯丙基硅烷的存在下，用路易斯酸处理环状烯醇碳酸酯，导致形成高烯丙基酮。结果表明，四氯化锆与烯丙基三甲基硅烷联用时，标题反应进行得较好。烯丙基化以高区域选择性发生，并且以良好至高的产率获得相应的高烯丙基酮。提出了一种反应机理，涉及的氧烯丙基阳离子等价物的脱羧形成。
A homoallylic ketone can be transformed and functionalized by various synthetic reactions, and thus, is regarded as one of the representative building blocks in organic chemistry. An additional route to access homoallylic ketones, namely, aLewisacid‐mediated decarboxylative allylation of cyclic enol carbonates, prepared by fixation of carbon dioxide onto propargyl alcohols, was developed in this work. The treatment of a cyclic enol carbonate with aLewisacid in the presence of an allylsilane resulted in the formation of a homoallylic ketone. It was found that the title reaction proceeded well by the combined use of zirconium tetrachloride with allyltrimethylsilane. The allylation occurred with high regioselectivity and the corresponding homoallylic ketones were obtained in good‐to‐high yields. A reaction mechanism involving the decarboxylative formation of an oxyallyl cation equivalent is proposed.