Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706, USA.
Chemistry. 2020 Nov 2;26(61):13783-13787. doi: 10.1002/chem.202002533. Epub 2020 Oct 1.
The addition of radicals to unsaturated precursors is a powerful tool for the synthesis of both carbo- and heterocyclic organic building blocks. The recent advent of mild ways to generate N-centered radicals has reignited interest in exploiting highly regio-, chemo-, and stereoselective transformations that employ these reactive intermediates. While the additions of aminyl, iminyl, and amidyl radicals to alkenes and alkynes have been well-studied, analogous additions to allenes are scarce. Allenes offer several attractive features, including potential for selective amidation at three distinct sites via judicious choice of precursor or radical source, the opportunity for axial-to-point chirality transfer, and productive trapping of vinyl or allyl radical intermediates to diversify functionality in the products. In this article, we report a regioselective addition of amidyl radicals to allenes to furnish an array of valuable N-heterocycle scaffolds.
在不饱和前体中添加自由基是合成碳环和杂环有机结构单元的有力工具。最近，温和的生成 N 中心自由基的方法的出现重新激发了人们对利用这些反应中间体进行高度区域选择性、化学选择性和立体选择性转化的兴趣。虽然氨基金属、亚胺基和酰胺基自由基与烯烃和炔烃的加成已经得到了很好的研究，但类似的加成到丙二烯上的研究却很少。丙二烯具有几个吸引人的特点，包括通过明智地选择前体或自由基源，在三个不同的位置进行选择性酰胺化的潜力、轴向到点手性转移的机会以及通过捕获乙烯基或烯丙基自由基中间体来增加产物功能的机会。在本文中，我们报道了酰胺基自由基对丙二烯的区域选择性加成，以提供一系列有价值的 N-杂环支架。
