18545-25-0Relevant academic research and scientific papers
Bright, Multi-responsive, Sky-Blue Platinum(II) Phosphors Based on a Tetradentate Chelating Framework
Liu, Lijie,Wang, Xiang,Wang, Nan,Peng, Tai,Wang, Suning
, p. 9160 - 9164 (2017)
A new class of highly efficient and stable, blue-phosphorescent PtII complexes based on a tetradentate chelating framework has been found to exhibit highly sensitive and reversible responses to multiple external stimuli including temperature, pressure, and UV irradiation with distinct phosphorescent color switching—from blue to red or white. Intermolecular excimer formation is the main origin of this intriguing multi-response phenomenon. Highly efficient singlet-oxygen sensitization by the PtII compounds yields UV-light-induced phosphorescence enhancement and color switching.
Production of Hydroxy Acids: Selective Double Oxidation of Diols by Flavoprotein Alcohol Oxidase
Fraaije, Marco W.,Martin, Caterina,Trajkovic, Milos
, p. 4869 - 4872 (2020/02/11)
Flavoprotein oxidases can catalyze oxidations of alcohols and amines by merely using molecular oxygen as the oxidant, making this class of enzymes appealing for biocatalysis. The FAD-containing (FAD=flavin adenine dinucleotide) alcohol oxidase from P. chrysosporium facilitated double and triple oxidations for a range of aliphatic diols. Interestingly, depending on the diol substrate, these reactions result in formation of either lactones or hydroxy acids. For example, diethylene glycol could be selectively and fully converted into 2-(2-hydroxyethoxy)acetic acid. Such a facile cofactor-independent biocatalytic route towards hydroxy acids opens up new avenues for the preparation of polyester building blocks.
Preparation of cis-Fused Tetrahydropyranyl Lactones via Palladium-Catalysed Cyclocarbonylation of Enediols
Cintulová, Daniela,Slahú?ková, Monika,Pa?trnák, Juraj,Prónayová, Na?a,Szolcsányi, Peter
supporting information, p. 755 - 762 (2017/02/15)
The stereoselective palladium-catalysed cyclocarbonylation of hex-5-ene-1,4-diols affords cis-fused bicyclic lactones only. Ring-opening with N,O-dimethylhydroxylamine hydrochloride gives the corresponding Weinreb amides, and their subsequent recyclisation provides advanced synthons for the prospective synthesis of decarestrictine L. The relative configurations of all the prepared tetrahydropyrans are determined by NOESY. The attempted transformations of lactones into methyl ketones leads to an unexpected furan, the formation of which is discussed.
Comparison of “on water” and solventless procedures in the rhodium-catalyzed hydroformylation of diolefins, alkynes, and unsaturated alcohols
Alsalahi,Trzeciak
, p. 41 - 48 (2016/07/06)
Catalytic systems containing Rh(acac)(CO)2 or Rh/PAA (PAA?=?polyacrylic acid) and hydrophobic phosphine (PPh3) were used in the hydroformylation of diolefins, alkynes, and unsaturated alcohols under solventless and “on water” conditions. The total yield of dialdehydes obtained from 1,5-hexadiene and 1,7-octadiene reached 99%, and regioselectivity towards linear dialdehydes was higher in the “on water” system. The tandem hydroformylation-hydrogenation of phenylacetylene led to the formation of saturated aldehydes (3-phenylpropanal and 2-phenylpropanal) at 98% conversion with a good regioselectivity towards the linear aldehyde in the “on water” reaction. In contrast, solventless conditions appeared better in the hydroformylation of 1-propen-3-ol. 4-Hydroxybutanal, formed in this reaction with an excellent selectivity, was next transformed to tetrahydrofuran-2-ol via a ring-closure process. Cyclic products were also obtained in hydroformylation of 1-buten-3-ol. In reaction of undec-1-ol and 2-allylphenol linear aldehydes were formed with the yield 69–87%. The hydroformylation of 3-buten-1-ol performed under “on water” conditions showed very good regioselectivity towards a linear aldehyde, 5-hydroxypentanal. Further cyclization of the aldehyde to tetrahydropyran-2-ol was observed.
Selective reduction of esters to aldehydes under the catalysis of well-defined NHC-iron complexes
Li, Haoquan,Misal Castro, Luis C.,Zheng, Jianxia,Roisnel, Thierry,Dorcet, Vincent,Sortais, Jean-Baptiste,Darcel, Christophe
supporting information, p. 8045 - 8049 (2013/08/23)
On a direct course to the aldehyde: Hydrosilylation catalyzed by a well-defined N-heterocyclic-carbene-iron complex under UV irradiation enabled the selective reduction of esters to aldehydes (see scheme; Bn=benzyl, Mes=mesityl). The low catalyst loading and very mild reaction conditions make this chemoselective transformation a promising alternative to the reduction of esters with diisobutylaluminum hydride. Copyright
A concise approach to the spiroiminal fragment of marineosins
Li, Guang,Zhang, Xun,Li, Qi,Feng, Pengju,Shi, Yian
supporting information, p. 2936 - 2938 (2013/07/25)
A concise approach to the spiroiminal fragment of marineosins A and B is described. The key steps involve an acid-catalyzed N-acyliminium ion cyclization and a Vilsmeier-Haack type reaction with Tf2O. The Royal Society of Chemistry 2013.
Selective photooxidation of diols with silica bound W10 O324 -
Maldotti,Molinari,Bigi
, p. 312 - 317 (2008/09/16)
The decatungstate anion W10 O324 - has been heterogenized on silica previously functionalized with different ammonium cations covalently bound to the surface of the solid support. These materials are investigated as photocatalysts for the oxygen-assisted oxidation of 1,3-butanediol and 1,4-pentanediol. Product distribution and adsorption experiments indicate that the polarity of the environment surrounding the photoactive anion plays a crucial role in controlling the adsorption of diols on the surface and, consequently, their reaction with the photoexcited decatungstate. Proper reaction conditions are found for obtaining more than 90% of 4-hydroxy-2-butanone from 1,3-butanediol and for stopping the oxidation of 1,4-pentanediol to 4-hydroxypentanal with good yield. The employed photocatalysts present a very good stability in repeated experiments.
Catalytic aerobic oxidation of diols under photo-irradiation: Highly efficient synthesis of lactols
Miyata, Atsushi,Furukawa, Mizuki,Irie, Ryo,Katsuki, Tsutomu
, p. 3481 - 3484 (2007/10/03)
Aerobic oxidation of 1, n- and 1,ω-diols with (ON)Ru(salen) 1 as the catalyst was found to give the corresponding lactols in almost quantitative yields. Furthermore, in the oxidation of 2,2-dimethylalkane-1,ω-diols, less sterically hindered ω-alcohols were found to be preferentially oxidized when (ON)Ru(salen) 6 was used as the catalyst. n-Decanol was preferentially oxidized in the presence of 2,2-dimethylpropanol also by using 6 as the catalyst.
New syntheses with magnesium hydride part 2: Pathways to new complex hydrides and aluminium hydride
Knott, Wilfried
, p. 629 - 634 (2007/10/03)
The reaction between autocatalytically prepared magnesium hydride (Tego Magnan) and aluminium halides in ethers generates a new class of reducing agents, i.e. magnesium aluminium hydridohalides. By choosing dioxane-1,4 as solvent a route to an aluminium hydride dioxane complex is opened. The new reducing agents show outstanding selectivity especially in the field of organosilicones, combined with a maximum of safety in their application.
Concise synthesis of cis- and trans-theaspirones via oxonium ion-initiated pinacol ring expansion
Paquette, Leo A.,Lanter, James C.,Wang, Hui-Ling
, p. 1119 - 1121 (2007/10/03)
The odoriferous principle of black tea has been produced from 2,2-dimethylcyclopentanone. The reaction sequence begins with 1,2-addition of 5-lithio-2-methyl-2,3-dihydrofuran to this ketone and immediate acid-catalyzed ring expansion of the resulting carbinols to a separable pair of spiro ethers. Individual conversion of these diastereomers to α,β-unsaturated ketones is followed by tandem condensation with the methyllithium-lithium bromide complex and oxidation with pyridinium chlorochromate.
