76644-52-5Relevant articles and documents
A further step to sustainable palladium catalyzed oxidation: Allylic oxidation of alkenes in green solvents
dos Santos Costa, Maíra,de Camargo Faria, Amanda,Mota, Rayssa L.V.,Gusevskaya, Elena V.
, (2021/09/14)
The palladium catalyzed oxidation of alkenes with molecular oxygen is a synthetically important reaction which employs palladium catalysts in solution; therefore, a solvent plays a critical role for the process. In this study, we have tested several green solvents as a reaction medium for the allylic oxidation of a series of alkenes. Dimethylcarbonate, methyl isobutyl ketone, and propylene carbonate, solvents with impressive sustainability ranks and very scarcely exploited in palladium catalyzed oxidations, were proved to be excellent alternatives for the solvents conventionally employed in these processes, such as acetic acid. Palladium acetate alone or in the combination with p-benzoquinone efficiently operates as the catalyst for the oxidation of alkenes by dioxygen under 5–10 atm. For most substrates, the systems in green solvents showed better selectivity for allylic oxidation products as compared to pure acetic acid; moreover, the reactions in propylene carbonate solutions occurred even faster than in acetic acid.
CHOLINE METABOLISM INHIBITORS
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Page/Page column 50; 102-103, (2020/07/05)
The present disclosure relates to compounds, compositions and methods for inhibiting choline metabolism, e.g., conversion of choline to trimethylamine. Disclosed herein are compounds, compositions, and methods for inhibiting choline metabolism, e.g., conversion of choline to TMA. Also disclosed herein are compounds, methods and compositions for inhibiting choline metabolism by gut microbiota resulting in reduction in the formation of trimethylamine (TMA) and trimethylamine N-oxide (TMAO).
Ligand's electronegativity controls the sense of enantioselectivity in BIFOP-X palladium-catalyzed allylic alkylations
Brüllingen, Eric,Neud?rfl, J?rg-Martin,Goldfuss, Bernd
supporting information, p. 15743 - 15753 (2019/10/19)
Palladium-catalyzed allylic alkylations of sodium dimethyl malonate with 1,3-diphenylallyl acetate, employing BIFOP-H (biphenylbisfencholphosphite) and analogue (i.e. BIFOP-X, X = D, Cl, CN, N3) ligands, all yield (S)-enantiomeric products, while alkylations to cyclohexenyl acetate yield the (R)-enantiomeric C-C coupling product (up to 91% yield, 70% ee). The fluoro derivative BIFOP-F however, "switches" the sense of enantioselectivity, yielding the (R)-enantiomer for 1,3-diphenylallyl acetate and the (S)-enantiomer for the cyclohexenyl acetate (up to 92% yield, 67% ee). Computational analyses of transition structures (M06-2X-D3/def2-TZVP//B3LYP-D3(BJ)/def2-SVP) for these Pd-catalyzed allylic alkylations reproduce the experimental preference of BIFOP-H (and analogue BIFOP-X ligands) for (R)- or (S)-enantiomeric products of 1,3-diphenylallyl or cyclohexenyl acetate, respectively. The "F-switch" of the sense of enantioselectivity from BIFOP-H to BIFOP-F is also apparent computationally and is found (NBO-analyses) to originate from lp(Pd) → σ?(P-O) or lp(Pd) → σ?(P-F) hyperconjugations. The higher electronegativity of F vs. H in BIFOP-X hence controls the sense of enantioselectivity of this Pd-catalyzed allylic alkylation.