Ergebnisse einschränken


Université de Neuchâtel

Calix[n]tetrahydrofuran[4-n]pyrrolidines : optimized synthesis via hydrogenation of calix[n]furan[4-n]pyrroles, conformational study and preliminary work on their transition metal complexes

Maupillier, William ; Neier, Reinhard (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2016.

An hydrogenation method for the reduction of the easy accessible meso-octaalkylporphirinogen (calix[4]pyrrole) has previously been reported in our group. This “standard method” leads to an unsatisfactory conversion to the saturated analogue, calix[4]pyrrolidine (18% yield determined by GC). However using large excess of the catalyst leads to total conversion. In order to study...

Université de Fribourg

Catalytic hydrogenation using abnormal N-heterocyclic carbene palladium complexes: catalytic scope and mechanistic insights

Heckenroth, Marion ; Khlebnikov, Vsevolod ; Neels, Antonia ; Schurtenberger, Peter ; Albrecht, Martin

In: ChemCatChem, 2011, vol. 3, no. 1, p. 167-173

Palladium complexes containing abnormally bound C4-bound dicarbene ligands have been exploited for catalytic alkene hydrogenation. Comparison to normally C2-bound homologues indicates that the carbene bonding mode critically influences the catalytic activity. Good catalytic performance in the hydrogenation of cis-disubstituted olefins and non-isomerizable terminal olefins under mild...

Université de Neuchâtel

Catalytic Hydrogenation of meso-Octamethylporphyrinogen (Calix[4]pyrrole)

Journot, Guillaume ; Letondor, Christophe ; Neier, Reinhard ; Stoeckli-Evans, Helen ; Savoia, Diego ; Gualandi, Andrea

In: Chemistry - A European Journal, 2010, vol. 16, no. 4, p. 4224-4230

Hydrogenation of meso-octamethylporphyrinogen (calix[4]pyrrole) with a number of heterogeneous catalysts under different experimental conditions has been investigated. GC-MS analyses of the reaction mixtures showed the formation of one to four products in low to moderate yields: three of them were diastereoisomers of the product derived from half-hydrogenation of the substrate, and displayed...

Université de Neuchâtel

Second Generation Artificial Hydrogenases Based on the Biotin-Avidin Technology: Improving Activity, Stability and Selectivity by Introduction of Enantiopure Amino Acid Spacers

Rusbandi, Untung E. ; Lo, Cheikh ; Skander, Myriem ; Ivanova, Anita ; Creus, Marc ; Humbert, Nicolas ; Ward, Thomas R.

In: Advanced Synthesis & Catalysis, 2007, vol. 349, no. 11-12, p. 1923-1930

We report on our efforts to create efficient artificial metalloenzymes for the enantioselective hydrogenation of N-protected dehydroamino acids using either avidin or streptavidin as host proteins. Introduction of chiral amino acid spacers - phenylalanine or proline - between the biotin anchor and the flexible aminodiphosphine moiety 1, combined with saturation mutagenesis at...

Université de Neuchâtel

Artificial Metalloenzymes for Enantioselective Catalysis Based on the Noncovalent Incorporation of Organometallic Moieties in a Host Protein

Ward, Thomas R.

In: Chemistry - A European Journal, 2005, vol. 11, p. 3798-3803

Enzymatic and homogeneous catalysis offer complementary means to produce enantiopure products. Incorporation of achiral, biotinylated aminodiphosphine-rhodium complexes in (strept)avidin affords enantioselective hydrogenation catalysts. A combined chemogenetic procedure allows the optimization of the activity and the selectivity of such artificial metalloenzymes: the reduction of...