catalyzed aldolreaction of trimethylsilylenolates with aldehydes is established in DMF or pyridine solvent by using a Lewis base such as lithium diphenylamide (Tables 4 and 5) or lithium 2-pyrrolidone (Tables 6–8). The effect of solvent suggests that this reaction proceeds via the pentacoordinated hypervalent silicate generated by the coordination of the above Lewis base to a trimethylsilylenolate. Successive
Lithium Pyrrolidone Catalyzed Aldol Reaction between Aldehyde and Trimethylsilyl Enolate
作者:Hidehiko Fujisawa、Teruaki Mukaiyama
DOI:10.1246/cl.2002.858
日期:2002.8
Lithium pyrrolidone catalyzed aldolreactionbetweentrimethylsilylenolates and aldehydes proceeded smoothly in a DMF or pyridine solvent to afford the corresponding aldols under weakly basic conditions.
Lithium Acetate-Catalyzed Aldol Reaction between Aldehyde and Trimethylsilyl Enolate in Anhydrous or Water-Containing<i>N</i>,<i>N</i>-Dimethylformamide
AcOLi catalyst, the aldolreaction in water-containing DMF was studied in detail. AcOLi and various metal carboxylates behaved as effective Lewis base catalysts in aldolreactionsbetweentrimethylsilylenolate and aldehydes in DMF-H 2 O (50:1) (Tables 6, 7). One of the most characteristic points of the above reaction that took place in water-containing DMF is that the aldehydes having a free amide
乙酸锂 (AcOLi) 催化的三甲基甲硅烷基烯醇化物和醛之间的醛醇反应在无水 DMF 或吡啶中顺利进行,在弱碱性条件下以良好至高产率提供相应的醛醇(表 1-5)。这种催化羟醛反应也可以通过使用其他金属羧酸盐顺利进行,这些金属羧酸盐通过用碳酸锂 (Li 2 CO 3 ) 处理羧酸很容易原位制备(表 2,方案 5)。为了展示温和易得的AcOLi催化剂的效果,详细研究了含水DMF中的羟醛反应。AcOLi 和各种金属羧酸盐在 DMF-H 2 O (50:1) 中三甲基甲硅烷基烯醇酯和醛之间的羟醛反应中充当有效的路易斯碱催化剂(表 6、7)。在含水DMF中发生的上述反应的最特征点之一是具有游离酰胺和羟基甚至羧基的醛反应平稳并以中等至高产率提供所需的醛醇29-31(表 8,条目 12-15)。由羧酸酯衍生的三甲基甲硅烷基烯醇化物在上述反应中表现得与优异的亲核试剂相似。这是路易斯碱催化醛醇反应的第一个例
Lithium Acetate-Catalyzed Aldol Reaction between Aldehyde and Trimethylsilyl Enolate
Lithium acetate-catalyzed aldol reaction between trimethylsilyl enolates and aldehydes proceeded smoothly in a DMF or pyridine solvent to afford the corresponding aldols in good to high yields under weakly basic conditions.
Aldolreactionsbetweentrimethylsilyl ketene acetals and aldehydes by using a catalytic amount of alkoxide anion proceeded smoothly to afford the corresponding aldols in DMF, indicating that the initially-formed aldolate anion effectively worked to catalyze the reaction. The “product-catalyzedaldolreaction”, a new class Lewis base-catalyzed aldolreaction, betweentrimethylsilyl ketene acetals and