Allylic gallium sesquibromides prepared by reduction of allylic bromides with gallium metal in the presence of a catalytic amount of indium, add to terminal alkynes with the aid of a tertiaryamine to give 1,4-dienes.
Stereoselective Iodocyclopropanation of Terminal Alkenes with Iodoform, Chromium(II) Chloride, and <i>N</i>,<i>N</i>,<i>N</i>‘,<i>N</i>‘-Tetraethylethylenediamine
Chemoselectivity of a reagent for (E)-olefination of aldehydesderived by reduction of iodoform with chromium(II) chloride in THF changes markedly by addition of TEEDA (N,N,N',N'-tetraethylethylenediamine), and trans-iodocyclopropanes are produced stereoselectively from terminal alkenes by treatment with the base-added reagent system. The iodocyclopropanation occurs only at terminal double bonds, and
通过加入 TEEDA(N,N,N',N'-四乙基乙二胺)和反式碘代环丙烷,通过在 THF 中用氯化铬 (II) 还原碘仿而得到的醛的 (E)-烯化试剂的化学选择性显着变化通过用加碱试剂系统处理,从末端烯烃立体选择性地产生。碘环丙烷化仅发生在末端双键处,同一分子中的二取代和三取代双键保持不变。醇、醚、甲硅烷基醚、酯、叔胺和酰胺基等官能团与反应条件相适应。