Phosphine/Palladium-Catalyzed Syntheses of Alkylidene Phthalans, 3-Deoxyisoochracinic Acid, Isoochracinic Acid, and Isoochracinol
摘要:
In this study we used sequential catalysis-PPh3-catalyzed nucleophilic addition followed by Pd(0)-catalyzed Heck cyclization-to construct complex functionalized alkylidene phthalans rapidly, in high yields, and with good stereoselectivities (E/Z ratios of up to 1:22). The scope of this Michael-Heck reaction includes substrates bearing various substituents around the alkylidene phthalan backbone. Applying this efficient sequential catalysis, we accomplished concise total syntheses of 3-deoxyisoochacinic acid, isoochracinic acid, and isoochracinol.
In this work, we present a carbonylative Sonogashirareaction of o-ethynyl benzyl alcohols and aryl iodides, followed by a cyclization process to selectively give carbonylmethylene isobenzofurans in high yields and in an atom-economic fashion. The reaction can be carried out in the absence of CuI, with a small amount of PdCl2(PPh3)2 (0.2–0.5 mol-%), using aryl iodides bearing both electron-withdrawing
在这项工作中,我们提出了邻乙炔基苄醇和芳基碘的羰基化 Sonogashira 反应,然后通过环化过程以高产率和原子经济的方式选择性地得到羰基亚甲基异苯并呋喃。该反应可以在不存在 CuI 的情况下,使用带有吸电子和给电子基团的芳基碘,使用少量 PdCl2(PPh3)2(0.2-0.5 mol%)进行。在两种可能的立体异构产物中,Z-异苯并呋喃衍生物是主要产物。但是,当反应扩展到仲醇时,观察到立体选择性的有趣转变。