Grubbs–Hoveyda type catalysts bearing a dicationic N-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

• Maximilian Koy,
• Hagen J. Altmann,
• Benjamin Autenrieth,
• Wolfgang Frey and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2015, 11, 1632–1638, doi:10.3762/bjoc.11.178

• ))) (Ru-1, Scheme 1) [21] turned out to be successful. To ensure the solubility in common organic solvents until the last step of the synthesis, the neutral precursor Ru-1 [21] was prepared in an improved one-step synthesis in 82% yield. Quarternization using 2.05 equiv of methyl trifluoromethanesulfonate

• = mesitylene). Single crystal X-ray structure of Ru-2. Co-solvent and disordered triflates have been omitted for clarity. Monomers used for biphasic ROMP reactions. Improved synthesis of Ru-1 and quarternization with methyl trifluoromethanesulfonate to Ru-2. Recycling of Ru-2 for continuous ROMP reactions

Quarternization of 3-azido-1-propyne oligomers obtained by copper(I)-catalyzed azide–alkyne cycloaddition polymerization

• Shun Nakano,
• Akihito Hashidzume and
• Takahiro Sato

Beilstein J. Org. Chem. 2015, 11, 1037–1042, doi:10.3762/bjoc.11.116

• . Keywords: 3-azido-1-propyne oligomer; CuAAC polymerization; hydrodynamic radius; methyl iodide; pulse-field-gradient spin-echo NMR; quarternization; Introduction The copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) efficiently yields 1,4-disubstituted-1,2,3-triazole from rather stable azides and

• was not possible to characterize the oligomer in solution. The observation that the AP oligomer is well soluble in strong acids suggests that protonation of the 1,2,3-triazole moieties improves its solubility. Thus we were motivated to study quarternization of the AP oligomer because it is known that

• the quarternized AP oligomer may be applied as a polymeric ionic liquid or a precursor of polymeric ionic liquids. In this study, we investigate quarternization of an AP oligomer with methyl iodide to obtain a soluble oligomer (Scheme 1b) and characterize the quarternized oligomer in dilute solutions

A divergent asymmetric approach to aza-spiropyran derivative and (1S,8aR)-1-hydroxyindolizidine

• Jian-Feng Zheng,
• Wen Chen,
• Su-Yu Huang,
• Jian-Liang Ye and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2007, 3, No. 41, doi:10.1186/1860-5397-3-41

• substitution occurred firstly, and the formation of the quaternary ammonium salt K [40] then favors the reductive debenzylation. This mechanism is supported by the following observations. First, in a similar case, Thompson et al observed that the formation of a mesylate resulted in spontaneous quarternization