Scalable synthesis of functionalised 2-pyridones via [4+2] cycloaddition reactions of 2-pyrazinones and alkynylboronates
作者:Wesley R.R. Harker、Patrick M. Delaney、Michael Simms、Matthew J. Tozer、Joseph P.A. Harrity
DOI:10.1016/j.tet.2012.12.010
日期:2013.2
The multigram synthesis of N-protected 2-pyridone boronic acid derivatives via a [4+2] cycloaddition of alkynylboronates with 2-pyrazinones is presented. The reactions are highly chemoselective, and generally highly regioselective although trimethylsilyl-substituted alkynylboronates have proven to be an exception. Nonetheless, in this latter case, separation of regioisomers was successfully accomplished
呈现了通过炔基硼酸酯与2-吡嗪酮的[4 + 2]环加成反应的N-保护的2-吡啶酮硼酸衍生物的多谱图合成。尽管三甲基甲硅烷基取代的炔基硼酸酯已被证明是一个例外,但是该反应是高度化学选择性的,并且通常是高度区域选择性的。然而,在后一种情况下,通过高性能逆流色谱法成功分离了区域异构体,从而可以分离出分析纯的2-吡啶酮。进行了三甲基甲硅烷基取代的2-吡啶酮硼酸酯的进一步衍生,提供了选择功能化支架的途径。