Samarium Diiodide in the Synthesis of Medium-Sized Rings - Carbocycles and Heterocycles by Intramolecular Addition of Samarium Ketyls to Alkynes
作者:Hans-Ulrich Reissig、Alexandra Hölemann
DOI:10.1055/s-2004-835657
日期:——
A series of alkynyl-substituted ketones and aldehydes was subjected to samarium diiodide in the presence of HMPA to study the scope and limitations of their ketyl-alkyne coupling. Seven- and eight-membered heterocycles such as 4, 6, 8, 25, 27, 29, 33, and 35 could be isolated in moderate to good yields. Other cyclization products were isolated in low yields only. The efficacy of the reductive cyclization
在 HMPA 存在下,对一系列炔基取代的酮和醛进行二碘化钐处理,以研究其炔基-炔偶联的范围和局限性。七元和八元杂环如 4、6、8、25、27、29、33 和 35 可以以中等至良好的产率分离。其他环化产物仅以低产率分离。还原环化的效果很大程度上取决于取代模式以及炔烃和羰基之间的间隔基中杂原子和/或苯环的存在。azocine 29 的第一次后续转化导致烯酮 38 或环氧化物 39 证明了该方法的合成潜力。