Rhodium-Catalyzed Dehydrogenative Silylation of Acetophenone Derivatives: Formation of Silyl Enol Ethers versus Silyl Ethers
作者:Karin Garcés、Ralte Lalrempuia、Víctor Polo、Francisco J. Fernández-Alvarez、Pilar García-Orduña、Fernando J. Lahoz、Jesús J. Pérez-Torrente、Luis A. Oro
DOI:10.1002/chem.201602760
日期:2016.10.4
[Rh(H)(Cl)(NSiN)(PCy3)] (Cy=cyclohexane) and [Rh(H)(CF3SO3)(NSiN)(coe)] (coe=cis‐cyclooctene). The [Rh(H)(CF3SO3)(NSiN)(coe)]‐catalyzed reaction of acetophenone with silanes performed in an open system was studied. Interestingly, in most of the cases the formation of the corresponding silyl enol ether as major reaction product was observed. However, when the catalytic reactions were performed in closed systems
报道了一系列铑-NSiN配合物(NSiN =双(吡啶-2-基氧基)甲基甲硅烷基fac配位),包括[Rh(H)(Cl)(NSiN)(PCy 3)的固态结构]( Cy =环己烷)和[Rh(H)(CF 3 SO 3)(NSiN)(coe)](coe =顺式-环辛烯)。[Rh(H)(CF 3 SO 3)(NSiN)(coe)]-苯乙酮与硅烷在开放系统中进行的催化反应进行了研究。有趣的是,在大多数情况下,观察到形成了相应的甲硅烷基烯醇醚作为主要反应产物。但是,当催化反应在密闭系统中进行时,有利于形成相应的甲硅烷基醚。此外,[Rh(H)(CF 3 SO 3)(NSiN)(coe)]与HSiMe 3反应的理论计算苯乙酮表明,甲硅烷基烯醇醚的形成在动力学上是有利的,而甲硅烷基醚是热力学的产物。脱氢甲硅烷基化需要通过金属-配体协同机制进行Si-H键的杂合裂解,这是决定速率的步骤。从配位的三甲基甲硅烷基硫酸盐
Cationic Ru–Se Complexes for Cooperative Si–H Bond Activation
作者:Marvin Oberling、Elisabeth Irran、Yasuhiro Ohki、Hendrik F. T. Klare、Martin Oestreich
DOI:10.1021/acs.organomet.0c00719
日期:2020.12.28
The preparation and structural characterization of mononuclear tethered ruthenium(II) complexes of type [(DmpSe)Ru(PR3)]+BArF4– (DmpSe = 2,6-dimesitylphenyl selenolate, ArF = 3,5-bis(trifluoromethyl)phenyl) are described. Unlike relevant known selenolate complexes, the reported family of complexes is cationic with a single monodentate selenolate ligand. The ability of these complexes to engage in cooperative
[(DmpSe)Ru(PR 3)] + BAr F 4 –(DmpSe = 2,6-二苯二甲硒基苯硒酸酯,Ar F的类型的单核束缚钌(II)配合物的制备和结构表征描述了= 3,5-双(三氟甲基)苯基。与已知的相关硒酸盐络合物不同,所报道的络合物家族是具有单个单齿硒酸盐配体的阳离子。研究了这些络合物在Ru-Se键上参与Si-H键协同活化的能力,并通过多核NMR光谱和X射线衍射对氢化硅烷加合物进行了充分表征。评估了这些配合物作为各种离子脱氢甲硅烷基化和氢化硅烷化反应的催化剂的有用性。在所有阶段,将新的配合物与其硫醇盐同系物[(DmpS)Ru(PR 3)] + BAr F 4 –(DmpS = 2,6-二甲磺基苯硫醇酯)。硒酸酯和硫醇酸酯配合物之间的差异很小,但是可以测量。较大的硒原子在Ru-Se键周围提供的空间比硫在Ru-S键处提供的空间更大,因此,硒酸酯络合物可以容纳空间上要求更高的氢硅烷。
Preparation of silyl enol ethers from acyloin derivatives using silyllithium reagents
作者:Bradley D. Robertson、Aaron M. Hartel
DOI:10.1016/j.tetlet.2008.01.133
日期:2008.3
A new method for the regioselective preparation of silyl enol ethers from acyloin derivatives using silyllithium reagents has been developed. Both dimethylphenyl- and methyldiphenylsilyllithium were found to be effective, the latter providing greater stereocontrol. The reaction is believed to proceed via Brook rearrangement assisted by expulsion of the adjacent leaving group. A number of acyclic acyloin
A Metal-Free Approach for the C–H Activation and Transfer Borylation of Electron-Rich Alkenes
作者:Vincent Desrosiers、Samantha M. Knight、Frédéric-Georges Fontaine
DOI:10.1021/acscatal.2c04305
日期:2022.11.4
Alkenyl boronates are ubiquitous reagents in organic synthesis, as they allow the formation of crucial bonds throughcross-couplingreactions. Transition-metal catalysis is the most common approach to this transformation; however, it has limitations in terms of selectivity and boron reagents. On the other hand, metal-free borylationreactions often require the use of harsh reagents, causing compatibility
Base-Free Dehydrogenative Coupling of Enolizable Carbonyl Compounds with Silanes
作者:C. David F. Königs、Hendrik F. T. Klare、Yasuhiro Ohki、Kazuyuki Tatsumi、Martin Oestreich
DOI:10.1021/ol301089r
日期:2012.6.1
A dehydrogenative coupling between enolizable carbonyl compounds and equimolar amounts of triorganosilanes catalyzed by a tethered ruthenium complex with a Ru-S bond is reported. The complex Is assumed to fulfill a dual role by activating the Si-H bond to release a silicon electrophile and by abstracting an a-proton from the intermediate silylcarboxonium ion, only liberating dihydrogen as the sole byproduct. Reaction rates are exceedingly high at room temperature with very low loadings of the ruthenium catalyst.