Search results for "reaktiomekanismi"

Understanding selective reduction reactions with heterogeneous Pd and Pt : climbing out of the black box

2016

Mechanistic Study of Stepwise Methylisocyanide Coupling and C-H Activation Mediated by a Low-Valent Main Group Molecule

2013

An experimental and DFT investigation of the mechanism of the coupling of methylisocyanide and C–H activation mediated by the germylene (germanediyl) Ge(ArMe6)2 (ArMe6 = C6H3-2,6(C6H2-2,4,6-Me3)2) showed that it proceeded by initial MeNC adduct formation followed by an isomerization involving the migratory insertion of the MeNC carbon into the Ge–C ligand bond. Addition of excess MeNC led to sequential insertions of two further MeNC molecules into the Ge–C bond. The insertion of the third MeNC leads to methylisocyanide methyl group C–H activation to afford an azagermacyclopentadienyl species. The X-ray crystal structures of the 1:1 (ArMe6)2GeCNMe adduct, the first and final insertion produc…

Carboxylate catalyzed isomerization of β,γ‐unsaturated N-acetylcysteamine thioesters

2022

We demonstrate herein the capacity of simple carboxylate salts – tetrametylammonium and tetramethylguanidinium pivalate – to act as catalysts in the isomerization of β,γ-unsaturated thioesters to α,β-unsaturated thioesters. The carboxylate catalysts gave reaction rates comparable to those obtained with DBU, but with fewer side reactions. The reaction exhibits a normal secondary kinetic isotope effect ( k 1H / k 1D = 1.065±0.026) with a β,γ−deuterated substrate. Computational analysis of the mechanism provides a similar value ( k 1H / k 1D = 1.05) with a mechanism where γ-reprotonation of the enolate intermediate is rate determining. peerReviewed