<i>N</i>-Methyl-Benzothiazolium Salts as Carbon Lewis Acids for Si−H σ-Bond Activation and Catalytic (De)hydrosilylation
作者:Valerio Fasano、James E. Radcliffe、Liam D. Curless、Michael J. Ingleson
DOI:10.1002/chem.201604613
日期:2017.1.1
N−Me‐Benzothiazolium salts are introduced as a new family of Lewis acids able to activate Si−H σ bonds. These carbon‐centred Lewis acids were demonstrated to have comparable Lewis acidity towards hydride as found for the triarylboranes widely used in Si−H σ‐bond activation. However, they display low Lewis acidity towards hard Lewis bases such as Et3PO and H2O in contrast to triarylboranes. The N−Me‐benzothiazolium
<i>N</i>-Methylacridinium Salts: Carbon Lewis Acids in Frustrated Lewis Pairs for σ-Bond Activation and Catalytic Reductions
作者:Ewan R. Clark、Michael J. Ingleson
DOI:10.1002/anie.201406122
日期:2014.10.13
N‐methylacridinium salts are Lewis acids with high hydride ion affinity but low oxophilicity. The cation forms a Lewis adduct with 4‐(N,N‐dimethylamino)pyridine but a frustrated Lewis pair (FLP) with the weaker base 2,6‐lutidine which activates H2, even in the presence of H2O. Anion effects dominate reactivity, with both solubility and rate of H2 cleavage showing marked anion dependency. With the optimal
N-Heterocyclic Carbene Organocatalysts for Dehydrogenative Coupling of Silanes and Hydroxyl Compounds
作者:Dongjing Gao、Chunming Cui
DOI:10.1002/chem.201301893
日期:2013.8.19
Go organic! N‐Heterocyclic carbene (NHC) 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene (IiPr) has been found to be an efficient and selective catalyst for the dehydrogenativecoupling of a wide range of silanes and hydroxyl groups to form SiO bonds under mild and solvent‐free conditions (see scheme). Mechanistic studies indicated that the activation of hydroxyl groups by the NHC is the most plausible
Aluminium trichloride catalyses the expeditious direct conversion of tetrahydropyranylethers to silyl ethers. This one-step transformation is chemoselective versus deprotection of the acetal and hydrosilylation of unsaturated carbon–carbon bonds, and can also be applied to linear acetals. A possible mechanism is tentatively proposed.
The dehydrogenative condensation of organosilicon hydrides with alcoholic substances catalyzed by rhodium (I) complex was found to furnish a convenient route for the preparation of silylated alcohols.