4070-75-1Relevant academic research and scientific papers
Comparison of the photocatalytic activity of novel hybrid photocatalysts based on phthalocyanines, subphthalocyanines and porphyrins immobilized onto nanoporous gold
Steinebrunner, David,Schnurpfeil, Günter,Thayssen, Jan,Tapia Burgos, Jorge Adrian,Wichmann, Andre,W?hrle, Dieter,Wittstock, Arne
, p. 11364 - 11372 (2021)
A series of different singlet oxygen photosensitizers was immobilized onto nanoporous gold powder with a mean pore size of 40 nmviacopper catalyzed azide-alkyne cycloaddition. The attachment of phthalocyanine and porphyrin derivatives was performed on the peripheral substituent of the macrocycle, whereas the subphthalocyanine derivatives were attachedviathe axial substituent with respect to the macrocyclic ring system. All obtained hybrid systems were studied in the photooxidation of 2,5-diphenylfuran as a chemical singlet oxygen quencher and showed increased photocatalytic activity compared to the same amount of the corresponding photosensitizer in solution due to photoinduced interactions of the plasmon resonance of the nanostructured gold support and the attached photosensitizer. The understanding of the different photophysical interactions depending on the coordination mode of the macrocycle as well as the position of the absorbance in the electromagnetic spectrum is an important point in the development towards highly active hybrid photocatalysts covering a broad absorption range within the spectrum of visible light.
Reaction of nitrous oxide with cyclopentadienyl complexes of cobalt, rhodium, and titanium
Leont'ev,Fomicheva,Proskurnina,Zefirov
, p. 496 - 498 (2001)
The reaction of nitrous oxide with some cyclopentadienyl compounds of cobalt, rhodium, and titanium was studied. The corresponding furans were obtained in low to moderate yields.
Rh(III)-Catalyzed Cascade Reactions of Sulfoxonium Ylides with α-Diazocarbonyl Compounds: An Access to Highly Functionalized Naphthalenones
Chen, Xi,Wang, Muhua,Zhang, Xinying,Fan, Xuesen
, p. 2541 - 2545 (2019)
An unprecedented cascade reaction of benzoyl sulfoxonium ylides with α-diazocarbonyl compounds leading to the formation of highly functionalized naphthalenones containing a β-ketosulfoxonium ylide moiety is presented. Promisingly, the naphthalenone derivative thus obtained was found to be a versatile intermediate toward diversely functionalized naphthalene derivatives including substituted 1-naphthol, 2-hydroxynaphthalen-1(2H)-one, naphthalen-1,2-dione, and 2-(methylsulfinyl)naphthalen-1-ol.
Facile Synthesis of Enantiopure Sugar Alcohols: Asymmetric Hydrogenation and Dynamic Kinetic Resolution Combined
Lin, Xin,Ma, Baode,Shao, Pan-Lin,Wang, Jiang,Wen, Jialin,Zhang, Xumu
supporting information, p. 18166 - 18171 (2020/08/21)
An unprecedented Ir/f-amphox-catalyzed asymmetric hydrogenation of racemic 2,3-syn-dihydroxy-1,4-diones is presented involving dynamic kinetic resolution, which produces (1R,2R,3R,4R)-tetraols. This protocol constitutes an efficient and straightforward approach to accessing sugar alcohols bearing four contiguous stereocenters. The strategy exhibits various advantages over existing methods, including excellent yields (up to 98 %), exceptional stereoselectivities (up to 99:1 dr, 99.9 % ee), operational simplicity and substrate generality. Moreover, the nature of the reaction was revealed as a stepwise transformation by in situ Fourier-transform infrared spectroscopy and isolation of intermediates.
Rhodium-Catalyzed 1,1-Hydroacylation of Thioacyl Carbenes with Alkynyl Aldehydes and Subsequent Cyclization
Zhou, Bingnan,Wu, Qiuyue,Dong, Ziyang,Xu, Jiaxi,Yang, Zhanhui
supporting information, p. 3594 - 3599 (2019/05/24)
A rhodium-catalyzed 1,1-hydroacylation of thioacyl carbenes with alkynyl and alkenyl aldehydes and subsequent 6-endo-trig/dig cyclization are realized, giving structurally diverse 4H-thiopyran-4-ones and 2,3-dihydro-4H-thiopyran-4-ones in moderate to good yields. The oxidative addition of Rh(I) to aldehydes is proposed to be the turnover-limiting step. Manipulations of estrones demonstrate the applications of our formal (3 + 3) transannulations in the structural modifications of natural products.
Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N-H-insertion products
Nikolaev, Valerij A.,Medvedev, Jury J.,Galkina, Olesia S.,Azarova, Ksenia V.,Schneider, Christoph
supporting information, p. 1904 - 1910 (2016/10/05)
Rh(II)-catalyzed reactions of aroyldiazomethanes, diazoketoesters and diazodiketones with α,β-unsaturated δ-aminoesters, in contrast to reactions of diazomalonates and other diazoesters, give rise to the Wolff rearrangement and/or oxidative cleavage of the initially formed N-H-insertion products. These oxidation processes are mediated by Rh(II) catalysts possessing perfluorinated ligands. The formation of pyrrolidine structures, characteristic for catalytic reactions of diazoesters, was not observed in these processes at all.
Copper-Catalyzed Cross-Coupling of Allylboronic Acids with α-Diazoketones
Das, Arindam,Wang, Dong,Belhomme, Marie-Charlotte,Szabó, Kálmán J.
, p. 4754 - 4757 (2015/10/12)
Copper-catalyzed cross-coupling of substituted allylboronic acids with α-diazoketones was studied. This allylation reaction is highly regioselective, providing the branched allylic product. The process involves creation of a new C(sp3)-C(sp3) bond by retaining the keto functional group of the α-diazoketone precursor.
Successively recycle waste as catalyst: A one-pot wittig/1,4-reduction/paal-knorr sequence for modular synthesis of substituted furans
Chen, Long,Du, Yi,Zeng, Xing-Ping,Shi, Tao-Da,Zhou, Feng,Zhou, Jian
, p. 1557 - 1560 (2015/03/30)
A one-pot tandem Wittig/conjugate reduction/Paal-Knorr reaction is reported for the synthesis of di- or trisubstituted furans. This novel sequence first demonstrates the possibility of successively recycling waste from upstream steps to catalyze downstream reactions.
Asymmetric organocatalytic aza-michael reactions of isatin derivatives
?ari, Sergei,Metsala, Andrus,Kudrjashova, Marina,Kaabel, Sandra,J?rving, Ivar,Kanger, T?nis
, p. 875 - 886 (2015/03/14)
Isatin was activated by derivatization to a Schiff base with aniline and used as an aza-Michael donor in organocatalytic asymmetric reactions with symmetric and nonsymmetric unsaturated 1,4-diketones. After hydrolysis (in situ), the N-substituted isatins were obtained in high yields (up to >95%) with high enantioselectivity (up to 95%).
Elemental reductants for the deoxydehydration of glycols
Michael McClain,Nicholas, Kenneth M.
, p. 2109 - 2112 (2014/07/21)
The elements zinc, iron, manganese, and carbon are demonstrated to be practical reductants for the oxorhenium catalyzed deoxydehydration (DODH) of biomass model polyols. These reductants and their oxidization products remain heterogeneous throughout the reaction, which aids in their separation. Their effectiveness is shown with the catalysts ammonium perrhenate and trans-[(Py)4Re(O)2]+Z- (1). Stoichiometric experiments with the Re(V) complex indicate a likely rhenium 5?7 oxidation cycle for the deoxydehydration of polyols reported herein.
