Geometry-Constrained Iminopyridyl Palladium-Catalyzed Hydroarylation of Alkynes to Prepare Tri-substituted Alkenes Using Alcohol as Reductant
作者:Ke Wu、Nan Sun、Baoxiang Hu、Zhenlu Shen、Liqun Jin、Xinquan Hu
DOI:10.1002/adsc.201800423
日期:2018.8.17
straightforward method to prepare tri‐substituted alkenes through palladium‐catalyzed hydroarylation of alkynes with aryl bromides. Diarylacetylenes and alkyl(aryl)acetylenes could be well hydroarylated with various aryl bromides in moderate to excellent yields. Mechanistic studies suggested that alcohol was the reductant to provide hydride through β‐H elimination. Gram scale reaction further demonstrated
Novel reactions of low valent titanium and zirconium reagents generated by reduction of Cp2TiCl2 and Cp2ZrCl2 with magnesium and 1,2-dibromoethane
作者:S. Achyutha Rao、M. Periasamy
DOI:10.1016/0022-328x(88)83026-2
日期:1988.9
The reduction of Cp2MCl2 (M = Ti or Zr) with Grignard grade magnesium and 1,2-dibromoethane in THF at 0° C gives the corresponding metallocene-ethylene complexes along with hydride species, as indicated by the reaction with diphenyl-acetylene to give 1,2-diphenyl-(E)-1-butene. The reactions of the Cp2ZrCl2/1,2-dibromobenzene/Mg system in THF with diphenylacetylene and norbornene are also described
A general and stereoselective method for synthesis of tri- and tetrasubstituted alkenes
作者:I Maciągiewicz、P Dybowski、A Skowrońska
DOI:10.1016/s0040-4020(03)00977-3
日期:2003.8
A convenient, general and stereoselectivesynthesis of trisubstituted alkenes and tetrasubstituted alkenes containing a cyanide function as well as trisubstituted episulphides have been elaborated. Methodology described for the preparation of these compounds is based on the corresponding readily available selenophosphates 1 and thiophosphates 2.
Regioselective Synthesis of α-Functional Stilbenes via Precise Control of Rapid <i>cis</i>–<i>trans</i> Isomerization in Flow
作者:Hyune-Jea Lee、Yuya Yonekura、Nayoung Kim、Jun-ichi Yoshida、Heejin Kim
DOI:10.1021/acs.orglett.1c00538
日期:2021.4.16
The rapid cis–trans isomerization of α-anionic stilbene was regioselectively controlled by using flow microreactors, and its reaction with various electrophiles was conducted. The reaction time was precisely controlled within milliseconds to seconds at −50 °C to selectively give the cis- or trans-isomer in high yields. This synthetic method in flow was well-applied to synthesize precursors of commercial
Reaction of 1,1-dihalogeno-2-phenyl-1-alkenes (I) with phenylmagnesium bromide in the presence of NiCl2(dppp) in THF has been studied. Mono-cross-coupling accompanied by partial reduction gave (E)-1,2-diphenyl-1-alkenes (III) as the major products. Use of a large excess of Grignardreagent increased the yields of III and the (Z)-isomers (II), with a decrease in the yield of double cross-coupling products
研究了1,1-二卤代-2-苯基-1-烯烃(I)与苯基溴化镁在NiCl 2(dppp)在THF中的反应。单交叉偶联伴随部分还原得到(E)-1,2-二苯基-1-烯烃(III)作为主要产物。使用大量过量的格氏试剂会增加III和(Z)异构体(II)的收率,而双交叉偶联产物1,1,2-三苯基-1-烯烃(IV )。对于PhMgBr与1,1-二溴-2-的反应,发现单苯基化产物的收率与双交叉偶联产物的收率的最高比率(II + III)/ IV = 36.5。摩尔比为12.0 / 1的苯丙烯(Ib)。描述了可能的反应机理。