Phenylene-coated organorhodium-functionalized magnetic nanoparticles are developed through co-condensation of chiral 4-(trimethoxysilyl)ethyl)phenylsulfonyl-1,2-diphenylethylene-diamine and 1,4-bis(triethyoxysilyl)benzene onto Fe3O4 followed complexation with [{Cp*RhCl2}2]. This magnetic catalyst exhibits excellent catalytic activity and high enantioselectivity in asymmetric transfer hydrogenation in aqueous medium. Such activity is attributed to the high hydrophobicity and the confined nature of the chiral organorhodium catalyst. The magnetic catalyst can be easily recovered by using a small external magnet and it can be reused for at least 10 times without loss of its catalytic activity. This characteristic makes it an attractive catalyst for environmentally friendly organic syntheses.
Enantioselective transformation of strong electron-withdrawing acyclic α-trifluoromethylimines to α-trifluoromethylamines through a ruthenium-catalyzed asymmetric transfer hydrogenation has been developed. The method described here is a facile catalytic process with sodium formate as a hydrogen resource and water-dimethylformamide as a cosolvent. The benefit of this enantioselective transformation affords a series of chiral α-trifluoromethylamines with high yields and excellent enantioselectivities (93-99% ee) under mild reaction conditions.
The reactivity of N‐heterocyclic carbene stabilized (NHC‐stabilized) aminochlorosilylene ArN(SiMe3)Si(IiPr)Cl (1, Ar = 2,6‐iPr2C6H3, IiPr = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) with selected Lewis acids and Lewis bases is described. Treatment of 1 with BH3·THF yielded 1·BH3 (2) quantitatively. Compound 2 is a rare example of an air‐insensitive silylene–borane adduct showing both acidic and basic properties of chlorosilylene in a single molecule. Crystals of 1–(CH2)3CH2OB(C6F5)3 (3) were obtained from the reaction of 1 with B(C6F5)3 in THF. For the first time, a frustrated Lewis pair (FLP) composed of a silylene and a substituted borane was observed to activate small molecules. Reaction of 1 with IMe4 (IMe4 = 1,3,4,5‐tetramethylimidazol‐2‐ylidene) at room temperature afforded silylene ArN(SiMe3)Si(IMe4)Cl (4), which represents a rare example of an NHC‐stabilized silylene synthesized through ligand exchange.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.