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。
Trimethylsilyl chloride-accelerated reduction and pinacol coupling of carbonyl compounds by means of samarium diiodide
作者:Toshio Honda、Miho Katoh
DOI:10.1039/a607774i
日期:——
The combination of samarium diiodide (SmI
2
) and
trimethylsilyl chloride (Me
3
SiCl) in THF–HMPA is found to
accelerate the reduction of sterically hindered and enolisable ketones,
and also to accelerate pinacolisation of the carbonyl compounds depending
on the reaction conditions.
REDUCTIVE COUPLING OF CARBONYL COMPOUNDS TO PINACOLS AND OLEFINS BY USING TiCl<sub>4</sub>AND Zn
作者:Teruaki Mukaiyama、Toshio Sato、Junichi Hanna
DOI:10.1246/cl.1973.1041
日期:1973.10.5
Aldehydes and ketones were reduced by low valent titanium compound, produced from TiCl4 and Zn, to give the corresponding pinacols and olefins in high yields.
醛和酮被由 TiCl4 和 Zn 生产的低价钛化合物还原,以高产率得到相应的频哪醇和烯烃。
Practical hydroxymethylation of aldehydes and ketones via pinacol cross-coupling reactions with paraformaldehyde
作者:Jeonghan Park、Steven F. Pedersen
DOI:10.1016/s0040-4020(01)88875-x
日期:——
method for the direct hydroxymethylation of aldehydes and ketones via pinacol cross-coupling with paraformaldehyde is described. The reaction is promoted by vanadium(II) ions which are conveniently generated from the reduction of VCl3(THF)3 with zinc dust. Excellent yields of terminal diols are obtained and stereoselective coupling is observed with some chiral aldehydes and ketones.
Synthesis of 2,5-dihydrofurans via alkylidene carbene insertion reactions
作者:Louise F. Walker、Ahmed Bourghida、Stephen Connolly、Martin Wills
DOI:10.1039/b111097g
日期:2002.3.25
The insertion reaction of alkylidene carbenes is demonstrated to be an effective method for the synthesis of 2,5-dihydrofuran ring systems. The best results have been obtained on substrates containing electron-withdrawing substituents, which appear less prone to the competing rearrangement reaction. This insight has led to the development of a new method for the synthesis of the core structure of the squalestatin–zaragozic acid natural products.