Diastereoselective Aldol Addition Using Boron Trichloride or Alkoxydichloroborane
作者:Hak-Fun Chow、Dieter Seebach
DOI:10.1002/hlca.19860690309
日期:1986.5.7
Under carefully controlled conditions, borontrichloride or alkoxydichloroborane/ethyldiisopropylamine in CH2Cl2 can be used to effect diastereoselective aldol additions of ethyl ketones to saturated, α, β-unsaturated, or aromatic aldehydes. The CC bond formation takes place with relative topicity ul (‘syn,’ configuration of the aldols), in selectivities ranging from 90 to 99% ds (Tables 1–3). Mechanistic
在精心控制的条件下,CH 2 Cl 2中的三氯化硼或烷氧基二氯硼烷/乙基二异丙胺可用于将乙基酮进行非对映选择性的醛醇缩合,形成饱和,α,β-不饱和或芳族醛。CC键的形成具有相对局部性ul(醛醇的“ syn ”构型),选择性范围为90%到99%ds(表1-3)。讨论了反应的机械方面。
The reaction of α,β-epoxy sulfoxides with lithium dimethylcuprate giving enolates: A novel synthesis of aldols
The aldols are synthesized from three compoments (1-chloroalkyl phenyl sulfoxide and two kinds of carbonyl compounds and ) through α,β-epoxy sulfoxides using lithiumdimethylcuprate as an electron-transfer reagent.
[GRAPHICS]Highly chemo-, diastereo-, and enantioselective borohydride reduction of 2-substituted-1,3-diketones was achieved in the presence of the optically active beta -ketoiminato cobalt complex catalysts to afford the optically active 2-substituted-3-hydroxyketones. The present catalytic and enantioselective reduction could provide an alternative potential for preparation of optically active ant aldol-type compounds.