Aqueous-phase hydroformylation of 1-octene using hydrophilic sulfonate salicylaldimine dendrimers
Water-soluble dendritic ligands based on tris-2-(5-sulfonato salicylaldimine ethyl)amine (5) and DAB-(5-sulfonato salicylaldimine) (6) (DAB = diaminobutane) were synthesized by means of Schiff base condensation and sulfonation reactions. These dendritic l
Hager, Emma B.,Makhubela, Banothile C.E.,Smith, Gregory S.
p. 13927 - 13935
(2013/01/15)
A new heterogeneous chiral (salen)manganese(III) system for enantioselective epoxidation of non-functionalized olefins
This communication describes the design and application of a novel catalytic epoxidation system derived from the initial immobilization of a homogeneous sulfonato (salen)Mn(III) complex on two solid carriers (silica gel and siliceous earth) and subsequent dispersion of the supported manganese complexes into ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) for recycling. The performance of chiral (salen)Mn(III) system in enantioselective epoxidation of olefins was investigated systematically. Even higher enantioselectivity than that of the homogeneous counterpart was obtained with similar catalytic activity. In particular, the best catalytic result is that the combination of the silica gel-supported (salen)Mn(III) catalyst and BMImPF6 affords 97-100% ee for epoxidation of α-methylstyrene, and high ee values were retained even after three cycles.