SmI2-catalysed cyclization cascades by radical relay
SmI2-catalysed cyclization cascades by radical relay
复制标题
DOI：
10.1038/s41929-018-0219-x
复制
发表时间：
2019-03-01
期刊：
影响因子：
37.8
通讯作者：
Procter, David J.
中科院分区：
文献类型：
--
作者：
Huang, Huan-Ming;McDouall, Joseph J. W.;Procter, David J.
自由基环化级联是用于构建一些社会上最珍贵的分子的复杂三维结构的强大工具。自40年前首次使用以来，SmI 2已被广泛用于还原自由基环化反应。不幸的是，SmI 2几乎总是必须大量过量使用，从而引起成本和浪费的问题。在这里，我们已经开发了由SmI 2催化的自由基环化级联，并利用自由基中继/电子催化策略。该方法不需要超化学计量的共还原剂，并且不需要添加剂。以优异的产率获得了包含多达四个连续立构中心的复杂环状产物，包括脱芳构化产物。机理研究支持单电子转移自由基机制。我们的策略提供了一个期待已久的解决方案，如何避免需要化学计量的SmI 2的问题，并建立了一个概念平台，在此基础上，其他催化自由基过程中使用无处不在的还原剂可以建立。
Radical cyclization cascades are powerful tools used to construct the complex three-dimensional structures of some of society's most prized molecules. Since its first use 40 years ago, SmI2 has been used extensively for reductive radical cyclizations. Unfortunately, SmI2 must almost always be used in significant excess, thus raising issues of cost and waste. Here, we have developed radical cyclization cascades that are catalysed by SmI2 and exploit a radical relay/electron-catalysis strategy. The approach negates the need for a super-stoichiometric co-reductant and requires no additives. Complex cyclic products, including products of dearomatization, containing up to four contiguous stereocentres are obtained in excellent yield. Mechanistic studies support a single-electron-transfer radical mechanism. Our strategy provides a long-awaited solution to the problem of how to avoid the need for stoichiometric amounts of SmI2 and establishes a conceptual platform on which other catalytic radical processes using the ubiquitous reducing agent can be built.