Studies in chlorin chemistry. II. A versatile synthesis of dihydrodipyrrins.
Studies in chlorin chemistry. II. A versatile synthesis of dihydrodipyrrins.
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研究二氢化学。
DOI：
10.1021/jo050907l
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Jacobi,PeterA
中科院分区：
文献类型：
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作者：
O'Neal,WilliamG;Roberts,WilliamP;Ghosh,Indranath;Jacobi,PeterA
二氢二吡啶是合成氢卟啉的关键组成部分，其中许多具有重要的生物活性。标题化合物以立体和区域选择性方式通过三步顺序制备，包括（1）Pd（0）催化的2-碘吡咯与γ-炔酸的偶联环化以提供所需取代模式的烯内酯，（2）使用Petasis试剂在内酯羰基上进行亚甲基化，以及（3）原位烯醇醚水解和所得产物的胺化1,4-二酮封闭吡咯啉环（九个例子）。每个步骤的产率通常都很高，尽管在未被偕取代芳构化为二吡咯甲烷的底物中是竞争性副反应。
Dihydrodipyrrins are key building blocks for the synthesis of hydroporphyrins, many of which have important biological activity. The title compounds were prepared in stereo- and regioselective fashion by a three-step sequence consisting of (1) Pd(0)-catalyzed coupling-cyclization of 2-iodopyrroles with γ-alkynoic acids to afford enelactones of the desired substitution pattern, (2) methylenation at the lactone carbonyl group employing the Petasis reagent, and (3) in situ enol-ether hydrolysis and amination of the resultant 1,4-diketone to close the pyrroline ring (nine examples). Yields for each step were generally high, although in substrates not blocked by geminal substitution aromatization to a dipyrromethane is a competing side reaction.