Insight into the role of fluorinated dendrimers in ruthenium(II) catalyst for asymmetric transfer hydrogenation: The stabilizing effects from experimental and DFT approach was written by Wang, Wei-Wei;Li, Zhi-Ming;Su, Ling;Wang, Quan-Rui;Wu, Ying-Li. And the article was included in Journal of Molecular Catalysis A: Chemical in 2014.Safety of Ethyl 3-oxo-3-(thiophen-2-yl)propanoate This article mentions the following:
Bis(tetrafluorophenoxy)benzyl-based fluorinated dendrimeric esters of a nonracemic (hydroxyphenylsulfonyl)diphenylethanediamine such as I (R = 2,3,5,6-F4C6H) were prepared as ligands for reusable enantioselective ruthenium hydrogenation catalysts. While the enantioselectivity of acetophenone hydrogenation varied little with dendrimer generation, the recyclability varied significantly; the ruthenium catalyst derived from [RuCl2(p-cymene)]2 and I was used 26 times with little decrease in yield or enantioselectivity, while the corresponding first- and third-generation ligands were only able to be used fewer than ten times. DFT calculations of the ruthenium chloride and hydride complexes of the second generation dendrimeric ligand indicated that the ruthenium complexes derived from I formed well-defined semi-rigid structures which incorporated π-π stacking and hydrogen bonding interactions to stabilize them. A dendrimeric ligand incorporating a bis(tetrafluorophenoxy)benzyloxybenzoate was prepared; the ruthenium catalyst derived from it was used 15 times at room temperature with little decrease in yield and enantioselectivity, but could only be used six times at 80°, while the ruthenium complex derived from I was used 23 times under similar conditions. In the experiment, the researchers used many compounds, for example, Ethyl 3-oxo-3-(thiophen-2-yl)propanoate (cas: 13669-10-8Safety of Ethyl 3-oxo-3-(thiophen-2-yl)propanoate).
Ethyl 3-oxo-3-(thiophen-2-yl)propanoate (cas: 13669-10-8) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Safety of Ethyl 3-oxo-3-(thiophen-2-yl)propanoate
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics