THE HIGHLY REGIOSELECTIVE COUPLING REACTION OF ALLYLIC ALCOHOLS WITH LITHIUM ENOLATE OF DITHIOESTERS USING 1-CHLORO-2-METHYL-<i>N</i>,<i>N</i>-TETRAMETHYLENEPROPENYLAMINE
作者:Tamotsu Fujisawa、Kazuto Umezu、Toshio Sato
DOI:10.1246/cl.1985.1453
日期:1985.10.5
1-Chloro-2-methyl-N,N-tetramethylenepropenylamine was found to be a good condensation reagent for the regioselective coupling reaction of allylic alcohols with lithium enolate of dithioesters under mild conditions to afford γ,δ-unsaturated dithioesters, which proceeds by a thio-Claisen rearrangement of S-allylic ketene dithioacetals initially formed.
<i>syn</i>
‐Selective Epoxidation of Chiral Terminal Allylic Alcohols with a Titanium Salalen Catalyst and Hydrogen Peroxide
作者:Fabian Severin、Giovanni M. Fusi、Christina Wartmann、Jörg‐Martin Neudörfl、Albrecht Berkessel
DOI:10.1002/anie.202201790
日期:2022.6.27
asymmetric epoxidation/kinetic resolution provides access to anti-configured terminal epoxy alcohols with high selectivity, no analogous syn-selective epoxidation process has been available. We report that this “missing link” is provided by a readily available titaniumsalalencatalyst. Besides allylic alcohols, allylic ethers are epoxidized with extreme syn-selectivity, at low catalyst loading, with
虽然 Sharpless 不对称环氧化/动力学拆分提供了以高选择性获得反构型末端环氧醇的途径,但目前还没有类似的顺选择性环氧化工艺。我们报告说,这种“缺失的环节”是由现成的钛 salalen 催化剂提供的。除了烯丙醇外,烯丙醚在低催化剂负载下以极高的顺式选择性环氧化,使用水性 H 2 O 2作为氧化剂。