A unified strategy for the synthesis of highly oxygenated diaryl ethers featured in ellagitannins
A unified strategy for the synthesis of highly oxygenated diaryl ethers featured in ellagitannins
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DOI：
10.1038/ncomms4478
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发表时间：
2014-03-01
影响因子：
16.6
通讯作者：
Yamada, Hidetoshi
中科院分区：
文献类型：
--
作者：
Hirokane, Tsukasa;Hirata, Yasuaki;Yamada, Hidetoshi
鞣花单宁是一个多酚家族，含有1,000多种天然产物。这些化合物中有近40%含有高度氧化的二芳基醚，这是其结构多样性的最关键元素之一。在这里，我们报告了一个统一的战略高度氧化的二芳基醚的合成特色鞣花单宁。该策略涉及氧杂迈克尔加成的酚邻醌结构单元，随后消除和还原芳构化。该结构单元的设计-没食子醛的卤代邻醌单缩酮-降低了邻醌的通常不稳定性并控制添加/消除。在其它可还原官能团存在下，还原芳构化以完美的化学选择性实现。该策略使得能够合成不同的二芳基醚。进行带有二芳基醚的天然鞣花单宁的第一全合成，以证明该策略增加了合成可用的鞣花单宁的数量。
Ellagitannins are a family of polyphenols containing more than 1,000 natural products. Nearly 40% of these compounds contain a highly oxygenated diaryl ether that is one of the most critical elements to their structural diversity. Here, we report a unified strategy for the synthesis of highly oxygenated diaryl ethers featured in ellagitannins. The strategy involves oxa-Michael addition of phenols to an orthoquinone building block, with subsequent elimination and reductive aromatization. The design of the building block-a halogenated orthoquinone monoketal of gallal-reduces the usual instability of orthoquinone and controls addition/ elimination. Reductive aromatization is achieved with perfect chemoselectivity in the presence of other reducible functional groups. This strategy enables the synthesis of different diaryl ethers. The first total synthesis of a natural ellagitannin bearing a diaryl ethers is performed to demonstrate that the strategy increases the number of synthetically available ellagitannins.