通过1,1-碳链化路线制备了一系列烯基硼烷,并将其用作路易斯酸组分,用于产生沮丧的路易斯对(FLP)。1-炔烃与B(C 6 F 5)3的反应得到RCH═C(C 6 F 5)B(C 6 F 5)2系统4a(R = n -C 3 H 7),4b(R = n -C 4 H 9),4c(R = Ph)和4d(R = t -C 4 H 9), 分别。在环境温度下,衍生自化合物4a – d的烯基硼烷/ t Bu 3 P FLP与二氢(2.5 bar)迅速反应。笨重的系统4D离开alkenylborane不饱和的C = C双键和,得到二氢裂解产物[吨卜3 PH] [吨BuCH═C(C 6 ˚F 5)BH(C 6 ˚F 5)2 ](10D) 。相比之下,体积较小的系统4a / t, Bu 3 P和4b / t在这些条件下,Bu 3 P分解成二氢,并干净地还原了它们的C═C双键,生成了相应的1-五氟苯基烷基氢硼酸盐[
Activation of Terminal Alkynes by Frustrated Lewis Pairs
作者:Chunfang Jiang、Olivier Blacque、Heinz Berke
DOI:10.1021/om9008636
日期:2010.1.11
The reactions of frustratedLewispairs (FLPs) derived from B(C6F5)3 and the bulky Lewis bases 2,2,6,6-tetramethylpiperidine (TMP), tri-tert-butylphosphine, and lutidine (Lut) with terminalalkynes (acetylene, phenylacetylene, 3-ethynylthiophene) were investigated. The FLPs TMP···B(C6F5)3,t-Bu3P···B(C6F5)3 and Lut···(C6F5)3 reacted with acetylene (HC≡CH) to yield the apparently thermodynamically more
受挫路易斯双(FLP信号)为B(C导出的反应6 ˚F 5)3和笨重的路易斯碱-2,2,6,6-四甲基哌(TMP),三-叔丁基膦,和二甲基吡啶(甩)与终端研究了炔烃(乙炔,苯乙炔,3-乙炔基噻吩)。FLP TMP ···(C 6 F 5)3,t- Bu 3 P···B(C 6 F 5)3和Lut ···(C 6 F 5)3与乙炔(HC≡CH)反应生成明显热力学更稳定的E异构体[ TMP H] [(C 6 F 5)2 B-C(C 6 F 5)═C(H)B(C 6 F 5)3 ](1- E),t- Bu 3 PC(H)═C(H)B(C 6 F 5)3(2- E ; 90%)和[ t- Bu 3 PH] [(C 6 F 5)2 B-C(C 6 F 5)═C(H)B(C 6 F 5)3 ](3- E ; 10%)和Lut C(H)═C(H)B(C 6 F 5)3(4- E) 。乙炔反应的机械途径建议从形成弱的B(C
Characterization of the Zwitterionic Intermediate in 1,1‐Carboboration of Alkynes
作者:Alessandro Bismuto、Gary S. Nichol、Fernanda Duarte、Michael J. Cowley、Stephen P. Thomas
DOI:10.1002/anie.202003468
日期:2020.7.27
intermediates generated by reaction of B(C6F5)3 with alkynes. The stepwise reactivity of the zwitterion provides new mechanistic insight for 1,1‐carboboration and wider B(C6F5)3 catalysis. Making use of intramolecular stabilization by a ferrocene substituent, we have characterized the zwitterionic intermediate in the solid state and diverted reactivity towards alkyne cyclotrimerization.
Lewis酸性硼烷与炔烃的反应是各种主基团转化过程中的关键步骤。Wrackmeyer反应是炔烃1,1-碳硼化反应,是这种原型转化。有人建议通过两性离子中间体进行1,1-碳硼化。我们报告了由B(C 6 F 5)3与炔烃反应生成的两性离子中间体的分离及光谱,结构和计算特征。两性离子的逐步反应性为1,1-碳硼化和更广泛的B(C 6 F 5)3提供了新的机理见解催化。利用二茂铁取代基的分子内稳定作用,我们表征了固态的两性离子中间体,并转移了对炔烃环三聚反应的反应性。