coupling of enolizable aldehydes with C‐alkynyl imines is realized affording the corresponding propargylic Mannich adducts of syn configuration, thus complementing previous methods that gave access to the anti‐isomers. The combination of proline and a urea Brønsted base cocatalyst is key for the reactions to proceed under very mild conditions (3–10 mol % catalyst loading, dichloromethane as solvent
可烯化的醛与C-炔基
亚胺的直接偶联可以实现相应的炔丙基曼尼希加成体的顺式构型,从而补充了以前的获得反异构体的方法。脯
氨酸和
尿素布朗斯台德碱助催化剂的组合对于在非常温和的条件(3-10 mol%催化剂负载,
二氯甲烷作为溶剂,-20°C,1.2摩尔当量的醛)和完全立体控制的条件下进行反应至关重要(顺式/反比率高达99:1; ee值高达99%)。还简要说明了加合物进一步
化学精制的一些可能性。