Ru-Based Catechothiolate Complexes Bearing an Unsaturated NHC Ligand: Effective Cross-Metathesis Catalysts for Synthesis of (<i>Z</i>)-α,β-Unsaturated Esters, Carboxylic Acids, and Primary, Secondary, and Weinreb Amides
作者:Zhenxing Liu、Chaofan Xu、Juan del Pozo、Sebastian Torker、Amir H. Hoveyda
DOI:10.1021/jacs.9b02318
日期:2019.5.1
compounds is illustrated through two representative applications: an eight-step, 15% overall yield, and completely Z-selective route leading to an intermediate that may be used in synthesis of stagonolide E (vs 11 steps, 4% overall yield and 91% Z, previously), and a five-step, 25% overall yield sequence to access a precursor to dihydrocompactin (vs 13 steps and 5% overall yield, formerly).
尽管取得了显着进展,但用于制备 (Z)-α,β-不饱和羰基化合物的烯烃复分解方法仍然很少,适用于合成多种生物活性分子。特别需要的是可以由基于钌的催化剂促进的转化,因为这样的实体将允许直接获得羧酸酯和酰胺或酸(与基于钼或钨的亚烷基相反)。在这里,我们详细介绍了如何根据通过计算和实验研究获得的机理洞察,发现一种易于获得的儿茶酚硫合钌配合物,该配合物可用于生成许多 α,β-不饱和羰基化合物,产率高达 81%,≥98: 2 Z/E 比率。我们首次证明,通过使用带有不饱和 N-杂环卡宾 (NHC) 配体的复合物,源自缺电子性更强的酯、酸和 Weinreb 酰胺(相对于伯酰胺或仲酰胺)的产物可以高效合成并具有高度立体化学控制。通过两个代表性应用说明了合成生物活性化合物的新进展的重要性:八步、15% 的总产率和完全 Z 选择性路线,导致可用于合成 stagonolide E 的中间体(vs 11步骤,4%