617-54-9Relevant articles and documents
Dowd,Kang
, p. 384 (1974)
Schwartz et al.
, p. 9269 (1972)
A Br?nsted acidic, ionic liquid containing, heteropolyacid functionalized polysiloxane network as a highly selective catalyst for the esterification of dicarboxylic acids
Rajabi, Fatemeh,Wilhelm, Christian,Thiel, Werner R.
supporting information, p. 4438 - 4444 (2020/08/10)
A Br?nsted acidic, ionic liquid containing, heteropolyanion functionalized polysiloxane network was formed by self-condensation of dodecatungstophosphoric acid and a zwitterionic organosilane precursor containing both imidazolinium and sulfonate groups. The resulting hybrid material POS-HPA-IL was investigated as a catalyst for the selective esterification of dicarboxylic acids.
Asymmetric hydrogenation of maleic acid diesters and anhydrides
Bernasconi, Maurizio,Mueller, Marc-Andre,Pfaltz, Andreas
supporting information, p. 5385 - 5388 (2014/06/09)
Asymmetric hydrogenation of maleic and fumaric acid derivatives with iridium catalysts based on N,P ligands provides an efficient route to chiral enantioenriched succinates. A new catalyst derived from a 2,6-difluorophenyl- substituted pyridine-phosphinite ligand was developed and enables the conversion of a wide range of 2-alkyl and 2-arylmaleic acid diesters into the corresponding succinates in high enantiomeric purity. Mixtures of cis/trans substrates can be hydrogenated in an enantioconvergent fashion with high enantioselectivity, and further enhances the scope of this transformation. The products are valuable chiral building blocks with a structural motif found in many bioactive compounds, such as metalloproteinase inhibitors. An attractive enantioselective route to 2-alkyl- and 2-aryl-substituted succinic acid derivatives is opened up by the asymmetric hydrogenation of maleic and fumaric acid derivatives, using the new catalyst [Ir(cod)L]BArF, derived from a 2,6-difluorophenyl-substituted pyridine-phosphinite ligand. The products are valuable chiral building blocks having a structural motif found in many bioactive compounds. cod=1,5-cyclooctadiene.
Nicotinamide-dependent Ene reductases as alternative biocatalysts for the reduction of activated alkenes
Durchschein, Katharina,Wallner, Silvia,MacHeroux, Peter,Schwab, Wilfried,Winkler, Thorsten,Kreis, Wolfgang,Faber, Kurt
supporting information, p. 4963 - 4968 (2013/01/14)
Four NAD(P)H-dependent non-flavin ene reductases have been investigated for their ability to reduce activated C=C bonds in an asymmetric fashion by using 20 structurally diverse substrates. In comparison with flavin-dependent Old Yellow Enzyme homologues, a higher degree of electronic activation was required, because the best activities were obtained with enals and nitroalkenes rather than enones and carboxylic esters. Although FaEO from Fragaria x ananassa (strawberry) and its homologue SlEO from Solanum lycopersicum (tomato) exhibited a narrow substrate spectrum, progesterone 5β-reductase (At5β-StR) from Arabidopsis thaliana (thale cress) and leukotriene B4 12-hydroxydehydrogenase (LTB4DH/PGR) from Rattus norvegicus (rat) appear to be promising candidates, in particular for the asymmetric bioreduction of open-chain enals, nitroalkenes and α,β-unsaturated γ-butyrolactones. Competing nitro reduction and non-enzymatic Weitz-Scheffer epoxidation were largely suppressed. Electronically activated alkenes have been stereoselectively reduced by using a single-enzyme-cofactor system employing nicotinamide-dependent non-flavin ene reductases. Copyright