Pd catalyzed couplings of "superactive esters" and terminal alkynes: Application to flavones and gamma-benzopyranones construction
Pd catalyzed couplings of "superactive esters" and terminal alkynes: Application to flavones and gamma-benzopyranones construction
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钯催化的“超活性酯”和末端炔烃的偶联：在黄酮和γ-苯并吡喃酮结构中的应用
DOI：
10.1016/j.molcata.2016.10.030
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发表时间：
2017
影响因子：
--
通讯作者：
Gao Ziwei
中科院分区：
文献类型：
--
作者：
Yang D;an;Wang Zhenhua;Wang Xiu;Sun Huaming;Xie Zunyuan;Fan Juan;Zhang Guofang;Zhang Weiqiang;Gao Ziwei
刘易斯碱、N-甲基吗啉（NMM）促进Pd催化的超活性酯1a-1 e和末端炔的Sonogashira偶联反应。该方法提供了一种在温和条件下用于广泛的酰化炔酰基酚化合物3a-3e的有效合成方案。机理研究清楚地表明，NNM稳定催化钯物种，并加速三嗪基团在交叉偶联反应的催化循环过程中的离开。此外，哌嗪还能有效地催化酰化炔酰基苯酚的6-内环化反应，实现了γ-苯并吡喃酮4aa-4 eg的多样性定向合成，产率为93-99%。
Lewis base,N-methylmorpholine (NMM) accelerated Pd-catalyzed Sonogashira coupling of steric hindered super active esters, 1a–1e, and terminal alkynes. This approach provided an efficient synthetic protocol for a broad array of acylatedo-alkynoylphenols compounds, 3a–3e, under moderate conditions. The mechanistic study clearly demonstrated that NNM stabilized the catalytic palladium species, and accelerated the leaving of triazine moiety during the catalytic cycle of the cross-coupling reactions. In addition, piperazine was found to efficiently catalyze the 6-endo cyclization of acylatedo-alkynoylphenols, which achieved the diversity oriented synthesis ofγ-benzopyranones, 4aa–4eg, with 93–99% yields.