我们报告了在双相中性相转移条件下使用叠氮化钠对羰基化合物进行氧化或脱羧氧化α-叠氮化的高性能I + / H 2 O 2催化。为了诱导更高的反应活性,尤其是对于1,3-二羰基化合物的α-叠氮化,我们设计了结构紧凑的异吲哚啉衍生的带有吸电子基团的季碘化铵催化剂。I + / H 2 O 2的非生产性分解途径催化量可以通过使用催化量的自由基捕获剂来抑制。这种氧化偶合耐受各种官能团,可以很容易地应用于结构多样的复杂分子的后期α-叠氮化。此外,我们实现了1,3-二羰基化合物的对映选择性α-叠氮化,这是手性次碘酸盐催化剂与对映选择性分子间氧化偶联的第一个成功实例。
作者:Tobias Harschneck、Sara Hummel、Stefan F. Kirsch、Philipp Klahn
DOI:10.1002/chem.201102680
日期:2012.1.23
An operationally simple, direct azidation of 1,3‐dicarbonyl compounds has been developed. The reaction proceeds readily under ambient conditions using sodium azide and an iodine‐based oxidant such as I2 or 2‐iodoxybenzoic acid (IBX)‐SO3K/NaI. In particular, the latter method, as a new and well‐balanced oxidizing agent, shows excellent functional group tolerance and substrate scope and thus allows access
已开发出一种操作简单的直接叠氮化1,3-二羰基化合物的方法。使用叠氮化钠和基于碘的氧化剂(例如I 2或2-碘氧基苯甲酸(IBX)-SO 3 K / NaI ),反应可在环境条件下轻松进行。尤其是,后一种方法作为一种新型且平衡良好的氧化剂,具有出色的官能团耐受性和底物范围,因此可以使用各种叔二叠氮基和2,2-双叠氮基1,3-二羰基化合物使用传统方法将更难以访问。由于含叠氮化物的产品容易与炔烃进行1,3-偶极环加成反应,因此我们的报告提出了一条通往敏感复杂分子类似物的新途径。
Azidation of β-Keto Esters and Silyl Enol Ethers with a Benziodoxole Reagent
作者:Maria Victoria Vita、Jérôme Waser
DOI:10.1021/ol401229v
日期:2013.7.5
The efficient azidation of β-keto esters and silyl enol ethers using a benziodoxole-derived azide transfer reagent is reported. The azidation of cyclic β-keto esters could be achieved in up to quantitative yields in the absence of any catalyst. In the case of less reactive linear β-keto esters and silyl enol ethers, complete conversion and good yields could be obtained by using a zinc catalyst.
We present an efficient synthesis of α-azido-β-dicarbonyl compounds from β-dicarbonylcompounds and trimethylsilyl azide, catalyzed by guanidinium hypoiodite. The reaction can be run in air at ambient temperature (up to 40 °C) and is not sensitive to moisture. The substrate scope is broad, including cyclic and linear β-dicarbonylcompounds, and the α-azide products are obtained in 55%–99% yield.