Zinc-Catalyzed Esterification of N-β-Hydroxyethylamides: Removal of Directing Groups under Mild Conditions
Zinc-Catalyzed Esterification of N-β-Hydroxyethylamides: Removal of Directing Groups under Mild Conditions
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N-β-羟乙基酰胺的锌催化酯化：温和条件下定向基团的去除
DOI：
10.1002/ejoc.201700748
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发表时间：
2017
影响因子：
2.8
通讯作者：
Mashima Kazushi
中科院分区：
文献类型：
--
作者：
Nishii Yuji;Hirai Takahiro;Fernandez Sarah;Knochel Paul;Mashima Kazushi
由于共振导致酰胺的惰性，涉及C-N键断裂的酰胺转化被认为是困难的反应。因此，强诱导效应和几何畸变合理地降低了共振稳定性以衰减C-N键。虽然这种活化的酰胺的转化已被深入研究，“未活化的”酰胺的反应系统是欠发达的。我们在此报告，三氟甲磺酸锌（II）[Zn（OTf）2]催化剂实现了广泛的未活化的叔酰胺的酯化与分子内酰基重排的协助。将该反应应用于在温和的反应条件下一锅去除各种基于酰胺的导向基团，以高产率提供相应的酯。
Amide transformations involving C–N bond cleavage are recognized as difficult reactions owing to the inert nature of amides resulting from resonance. Accordingly, a strong inductive effect and geometrical distortion reasonably decrease the resonance stabilization to attenuate the C–N linkage. Although the conversion of such activated amides has been studied intensively, reaction systems for “unactivated” amides are underdeveloped. We herein report that a zinc(II) trifluoromethanesulfonate [Zn(OTf)2] catalyst achieves the esterification of a wide range of unactivated tertiary amides with the assistance of intramolecular acyl rearrangement. The reaction was applied to the one‐pot removal of various amide‐based directing groups under mild reaction conditions to afford the corresponding esters in high yields.