<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
Desilylation procedure via a naphthalene-catalysed lithiation reaction
作者:Cherif Behloul、David Guijarro、Miguel Yus
DOI:10.1016/j.tet.2005.03.145
日期:2005.7
naphthalene, in THF, at 0 °C led, after hydrolysis, to the recovery of the free alcohols, amines and thiols in very good yields. At least a phenyl group was required in the silyl protecting group for the success of the reaction. Some polyfunctionalised starting materials have successfully been deprotected. The stereochemical outcome of the deprotection of a silylated chiral secondary alcohol has also been
An efficient method for the dehydrogenative coupling of silanes with alcohols under photocatalysis was developed. The reaction proceeded in the presence of Ru(bpy)3Cl2 (0.5 mol%) under visible light irradiation in acetonitrile at room temperature. The developed methodology was also applicable for the synthesis of silanols using water as a coupling partner.
Hydrosilylation of carbonyl compounds with hydrosilane is efficiently catalyzed by inorganic solid acids and bases such as Fe3+ ion-exchanged montmorillonite and hydroxyapatite (Ca10(PO4)6(OH)2) at reaction temperatures between 25 and 90 °C. Enones are also selectively hydrosilylated in the presence of hydroxyapatite to afford the corresponding 1,2-addition products in high yields.
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.