Chloroboration and allied reactions of unsaturated compounds
作者:F. Joy、M.F. Lappert、B. Prokai
DOI:10.1016/s0022-328x(00)85153-0
日期:1966.6
The reactions of boron halides (Cl, Br) and of some organoboron chlorides with olefins have been investigated. Detailed results are presented on cyclohexene, allene, 1,5-cyclooctadiene, norbornadiene, cyclooctatetraene, and cycloheptatriene. It is clear that boron trichloride reacts only with the most reactive of olefins (the last three), so that the first-formed product may react further and prevent
Site‐Fixed Hydroboration of Terminal and Internal Alkenes using BX
<sub>3</sub>
/
<sup>
<i>i</i>
</sup>
Pr
<sub>2</sub>
NEt**
作者:Sida Li、Chenyang Hu、Xin Cui、Jiong Zhang、Liu Leo Liu、Lipeng Wu
DOI:10.1002/anie.202111978
日期:2021.12.6
A novel and general method for the hydroboration of alkenes, including arylalkenes, 1,1-disubstitutedalkenes, aliphatic alkenes, and bio-derived alkenes, using BX3 as the boration reagent in the presence of iPr2NEt is reported. The reaction was also applied to the synthesis of linear and branched 1,n-diborylalkanes. The reaction is thought to proceed by a frustrated Lewis pair type single-electron-transfer
2-diyl-bridged A-frame complexes [Pt2X2(μ-1,2-B2(NMe2)2)(μ-dmpm)2]. X-ray crystallographic studies of these (BY)n-bridged complexes show structural trends depending on the steric demands of Y and the nature of X. Analysis of higher-order 31P NMR satellites provided information on JP–Pt and JPt–Pt coupling constants, the latter correlating with the Pt⋯Pt distance. All (di)boranediyl complexes also proved unstable
一系列硼烷二基桥接的二铂A框架络合物[Pt 2 X 2(μ-BY)(μ-dmpm)2 ](X = Cl,Br,I; Y =芳基,烷基,氨基,卤素; dmpm =双(二甲基膦基)甲烷)是通过将BX 2 Y二次氧化加成到[Pt 2(nbe)2(μ-dmpm)2 ](nbe =降冰片烯)或桨轮络合物[Pt 2(μ-dmpm)中而合成的)3 ]。类似地,将B 2 X 2(NMe 2)2(X = Cl,Br)添加到[Pt 2(nbe)2(μ-dmpm)2]提供访问乙硼烷-1,2-二基桥连的A-帧络合物[PT 2 X 2(μ-1,2--B 2(NME 2)2)(μ-DMPM)2 ]。这些(BY)n桥联配合物的X射线晶体学研究表明,结构趋势取决于Y的空间需求和X的性质。对高阶31 P NMR卫星的分析提供了有关J P–Pt和J Pt–的信息。 Pt耦合常数,后者与Pt⋯Pt距离相关。还证明所有(二)硼烷二基配合物对桥接成功的“
Hydroboration with Haloborane/Trialkylsilane Mixtures
作者:Raman Soundararajan、Donald S. Matteson
DOI:10.1021/om00009a018
日期:1995.9
Trialkylsilanes or dialkylsilanes react rapidly with boron trichloride in the absence of ethereal solvents or other nucleophiles to form unsolvated dichloroborane. If no substrate is present, dichloroborane disproportionates to trichloroborane and two geometric isomers of chloroborane dimer, which in turn yield monochlorodiborane and, slowly but irreversibly, diborane. All of the B-H compounds in the mixture except diborane are highly active hydroborating agents. With alkenes in the presence of sufficient boron trichloride, the products are alkyldichloroboranes. These are free from detectable contamination by dialkylchloroboranes unless more than 1 mol of hydride is present. Similar hydroboration of terminal acetylenes can be controlled to yield either (E)-1-(dichloroboryl)alkenes or 1,1-bis(dichloroboryl)alkanes, each free from significant contamination by the other. Alkyldichloroboranes with trialkylsilanes at 25 degrees C produce alkylmonochloroboranes, detected by B-11 NMR. 1,1-Bis(dichloroboryl)alkanes similarly yield 1,1-diborylalkane dimers. An alkylmonochloroborane can hydroborate a second alkene to form a dialkylchloroborane. For this purpose, differing alkyl groups may be introduced in either order, regardless of their relative steric properties. With 2 mol of trialkylsilane, alkyldichloroboranes are converted to alkylborane dimers. Boron tribromide and its bromoborane derivatives behave similarly to the chloro compounds in the examples tested.