Enantioselective Hydroformylation of 1-Alkenes with Commercial Ph-BPE Ligand
摘要:
A rhodium complex, in conjunction with commercially available Ph-BPE ligand, catalyzes the branch-selective asymmetric hydroformylation of 1-alkenes and rapidly generates alpha-chiral aldehydes. A wide range of terminal olefins Including 1-dodecene were examined, and all delivered high enantioselectivity (up to 98:2 er) as well as good branch:linear ratios (up to 15:1).
Strategies for the Generation of Molecularly Imprinted Polymeric Nitroxide Catalysts
摘要:
[GRAPHICS]Two strategies for preparing catalytically active molecularly imprinted nitroxide-containing polymers are outlined. Both strategies rely upon the thermal rearrangement chemistry of tertiary amine N-oxides. To this end, several polymers were prepared and the polymeric nitroxides were revealed by oxidation with m-CPBA. All of the resulting polymeric catalysts proved to be competent mediators of the oxidation of alcohols.
A significant improvement in Rh-catalyzed hydroformylation of very hydrophobicalkenes was achieved using a biphasic catalyticsystem consisting of a substrate-containing organic phase and a catalyst-containing hydrogel phase [consisting of poly(ethylene glycol) 20000 (PEG20000) and α-cyclodextrin (α-CD)]. The catalytic performance of the Pickering emulsion that resulted from the formation of α-CD/PEG20000
Breaking with conventional wisdom: Hydroformylationcatalysts are generally based on rhodium; earlier, cobalt was used. Iridium, which is less expensive than rhodium, was considered too unreactive. However, iridium/phosphine complexes have now been shown to form active catalysts for the hydroformylation of olefins under mild conditions (see scheme; R1, R2=H, alkyl, aryl; R3=H, alkyl). Competing hydrogenation
打破常规观点:加氢甲酰化催化剂通常基于铑;较早时使用钴。铱比铑便宜,被认为太活泼了。然而,现已显示铱/膦配合物可在温和条件下形成用于烯烃加氢甲酰化的活性催化剂(参见方案; R 1,R 2= H,烷基,芳基; R 3= H,烷基)。竞争性的氢化副反应可以得到抑制。
Water-soluble phosphane-substituted cyclodextrin as an effective bifunctional additive in hydroformylation of higher olefins
displaced upon coordination to rhodiumcomplexes. The efficacy of the resulting Rh-complex coordinated by β-CD-based phosphanes was assessed in Rh-catalyzed hydroformylation of higherolefins. The catalytic system proved to be far more successful and efficient than a system consisting of supramolecularly interacting phosphanes and CDs. The catalytic activity was up to 30-fold higher while the chemo- and regioselectivities
Super long-term highly active and selective hydroformylation in a room temperature-solidifiable guanidinium ionic liquid with a polyether tag
作者:Xin Jin、Daoxing Yang、Xinfu Xu、Zhiqiang Yang
DOI:10.1039/c2cc30909b
日期:——
Here we report a novel room temperature-solidifiable guanidinium methanesulfonate with a polyether tag and its use in Rh-catalysed biphasic hydroformylation of higher olefins. This novel ionic liquid can efficiently immobilize the Rh-TPPTS catalyst and render super long-term high activity and chemoselectivity, and no significant loss of activity, selectivity or Rh was observed after thirty-five cycles.