我们在这里报告了醛之间的催化不对称迭代和多米诺交叉羟醛反应,具有高度的稳健性、灵活性和通用性。Cu(I)-DTBM-SEGPHOS 复合物催化受体醛和由供体醛衍生的硼烯醇化物之间的不对称交叉羟醛反应,该反应是通过 Ir 催化的烯丙氧基硼酸酯异构化产生的。可以重复使用醛醇产物作为随后不对称醛醇反应的受体底物的单元过程。双醇醛反应的供体醛和立体选择性可以以逐步的方式灵活切换。此外,使用适量的供体和胺添加剂,可以在一锅法中进行不对称的三重和四重醛醇反应,通过控制多达八个立体中心快速拉长碳骨架。该方法可用于直接合成对映异构和非对映异构富集的 1,3-多元醇。
Dip in! A Rh/dippf catalyst generates aldehyde‐derived enol boranes at ambient temperature by isomerization of allyloxy‐ and homoallyloxyboranes. A one‐pot isomerization/cross‐aldol sequence provides aldehyde–aldehyde adducts in good yield with syn selectivity. Direct use of primary allylic and homoallylic alcohols was also achieved.
Rh-Catalyzed AldehydeAldehyde Cross-Aldol Reaction under Base-Free Conditions: In Situ Aldehyde-Derived Enolate Formation through Orthogonal Activation
The chemoselective generation of aldehyde‐derived enolates to realize an aldehydealdehyde cross‐aldol reaction is described. A combined Rh/dippf system efficiently promoted the isomerization/aldol sequence by using primary allylic, homoallylic, and bishomoallylic alcohols; secondary allylic and homoallylic alcohols; and trialkoxyboranes that were derivedfrom primary allylic and homoallylic alcohols