作者:Teruaki Mukaiyama、Nobuharu Iwasawa、Rodney W. Stevens、Toru Haga
DOI:10.1016/s0040-4020(01)82423-6
日期:1984.1
A highly diastereoselective cross aldolreaction is developed using divalent tin enolates formed from stannous trifluoromethanesulfonate and carbonyl compounds. The reaction is extended to a highly enantioselective cross aldolreaction employing chiral diamines derivedfrom (S)-proline as ligands.
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。
Gallium(III) Triflate Catalyzed Diastereoselective Mukaiyama Aldol Reaction by Using Low Catalyst Loadings
A mild method for the diastereoselectiveMukaiyamaaldolreaction is reported. By using a lowloading of the gallium(III) triflatecatalyst (down to 0.01 mol-%), the transformation proceeds efficiently to afford the corresponding β-hydroxy ketones in yields up to 92 %. To the best of our knowledge, this is the first report of a metal triflate acting as a safe, bench-stable, and slow-releasing source
A method for the stereospecific conversion of 1,3-diols into oxetanes
作者:Tajassus Aftab、Christabel Carter、Jennifer Hart、Adam Nelson
DOI:10.1016/s0040-4039(99)01840-7
日期:1999.12
Diastereomerically pure 1,3-diols were converted into the corresponding orthoesters and reacted with acetyl bromide to give bromoacetates with inversion of configuration at a benzylic position. Methanolysis and cyclisation gave diastereomerically pure 2,4-disubstituted oxetanes.
Titanium tetraiodide-promoted reductive enolate formation from α-tosyloxy ketone derivatives and subsequent aldol reaction of the resulting enolates with aldehydes gave β-hydroxy ketones.