Rhodium-Catalysed Coupling of Allylic, Homoallylic, and Bishomoallylic Alcohols with Aldehydes and<i>N</i>-Tosylimines: Insights into the Mechanism
作者:Nanna Ahlsten、Belén Martín-Matute
DOI:10.1002/adsc.200900448
日期:2009.11
alkenols followed by reaction with aldehydes or N-tosylimines catalysed by rhodiumcomplexes has been studied. The catalytically active rhodiumcomplex is formed in situ from commercially available (cyclooctadiene)rhodium(I) chloride dimer [Rh(COD)Cl]2. The tandem process affords aldol and Mannich-type products in excellent yields. The key to the success of the coupling reaction is the activation of
已经研究了烯醇的异构化,然后与铑络合物催化的醛或N-甲苯胺反应。催化活性的铑配合物是由可商购的(环辛二烯)氯化铑(I)二聚体[Rh(COD)Cl] 2原位形成的。串联过程以优异的产率提供了羟醛和曼尼希型产品。于偶联反应的成功的关键是,催化剂的活化通过与postassium叔丁醇(叔丁醇钾),这促进了催化循环通过醇盐,而不是铑的氢化物。该机制使不需要的副产物的形成最小化。该机制已被1研究1 H NMR光谱和氘标记实验。
Diastereoselective Aldol and Reformatsky Reactions of<b><i>α</i></b>-Halo Carbonyl Compounds and Aldehydes Mediated by Titanium(II) Chloride
Highly diastereoselective aldol reactions of α-bromo ketones with several aldehydes were successfully carried out by using a combination of titanium(II) chloride and copper or sodium iodide in dichloromethane-pivalonitrile at low temperature. Similarly, Reformatskyreactions of α-bromo thioester with aliphatic aldehydes proceeded to afford β-hydroxy thioesters in good yields under mild conditions.
通过在低温下在二氯甲烷-新戊腈中使用氯化钛 (II) 和碘化铜或碘化钠的组合,成功地进行了 α-溴酮与几种醛的高度非对映选择性羟醛反应。类似地,α-溴硫酯与脂肪醛的 Reformatsky 反应在温和条件下以良好的产率得到 β-羟基硫酯。
Chiral Phosphoramide-Catalyzed Aldol Additions of Ketone Enolates. Preparative Aspects
作者:Scott E. Denmark、Robert A. Stavenger、Ken-Tsung Wong、Xiping Su
DOI:10.1021/ja984123j
日期:1999.6.1
Trichlorosilyl enolates of ketones (enoxytrichlorosilanes) were demonstrated to be highly reactive aldoladdition reagents. Trichlorosilyl enolates of cyclohexanone (E-enolate) and propiophenone (Z-enolate) reacted readily at room temperature with a wide variety of aldehydes to afford aldoladdition products in high yield and diastereoselectivity (E → syn, Z → anti). These reactions were shown to be
Dibutyltin dimethoxide-catalyzed aldol reaction of enol trichloroacetates
作者:Akira Yanagisawa、Takayuki Sekiguchi
DOI:10.1016/s0040-4039(03)01840-9
日期:2003.9
A catalytic aldol condensation of aldehydes with enol trichloroacetates was achieved usingdibutyltindimethoxide as a novel catalyst in a mixed solvent consisting of THF and MeOH. Various β-hydroxy ketones were diastereoselectively obtained in high yields up to 99%.
The Aldol Reaction of Silyl Enol Ethers with Aldehydes in Aqueous Media
作者:Shū Kobayashi、Iwao Hachiya
DOI:10.1016/s0040-4039(00)91691-5
日期:1992.3
The aldol reaction of silyl enol ethers with aldehydes is successfully carried out in aqueous media by using a lanthanide trifluoromethanesulfonate as a catalyst. Water soluble aldehydes are applicable and the catalyst can be recovered and reused in this reaction.