Influence of External Ligands and Auxiliaries on the Reactivity of Low-Valent Titanium in McMurry Reaction: Selectivity and Mechanistic Profile
作者:N. Balu、S. K. Nayak、A. Banerji
DOI:10.1021/ja9535221
日期:1996.1.1
auxiliaries also resisted deoxygenation completely to give the pinacols in higher yields and better diastereoselectivity, as compared to pyridine-modified LVT system. Amongst these modified reagents, the LVT−catechol (1:1) system was found to be the most efficient combination for total pinacolization of aromatic carbonyl compounds, even under refluxing conditions. The actual titanium reagent responsible
已经探索了各种外部配体/助剂对低价钛 (LVT) 试剂 (McMurry 偶联) 介导的还原羰基偶联反应的影响。从 Tyrlik 的 TiCl3-Mg-THF 系统产生的 LVT 物质已被选择用于反应性调整试验。我们的研究表明,将大约 10 当量的吡啶(一种 π 受体配体)与 TiCl3 结合到 THF 溶剂化 LVT 试剂中可以阻止苯乙酮在中间频哪醇阶段的还原二聚化。与吡啶修饰的 LVT 系统相比,通过共价结合的单羟基、1,2-和 1,3-二羟基助剂对 LVT 种类的调节也完全抵抗脱氧,从而以更高的产率和更好的非对映选择性得到频哪醇。在这些改性试剂中,LVT-邻苯二酚 (1: 1) 系统被发现是芳香羰基化合物总频哪醇化的最有效组合,即使在回流条件下也是如此。实际负责的钛试剂...