328 research outputs found
Revisiting Reduction of CO 2 to Oxalate with First-Row Transition Metals: Irreproducibility, Ambiguous Analysis, and Conflicting Reactivity
No full textLes premières étapes de la réforme économique en RDA
No full textThe first stages of the GDR's economic reform
With the upturn of October 1989, new proposals for economic reform came to the fore in the GDR. But as January 15th, 1990, no overall economic design has so far been translated into hard fact. Having listed the projects either in course of implementation or completed, the author concludes that there are several areas of uncertainty, concerning energy policy, Plan and market relations, the question of German unity, the reduction of the county's debt, and current convertibility. Only a genuine political reform can hope to produce economic reform in the GDR.Avec le tournant opéré en octobre 1989, de nouvelles propositions de réformes économiques ont vu le jour en R.D.A. Mais à la date du 15 janvier 1990, aucune conception économique d'ensemble ne s'est encore traduite concrètement dans les faits. Après avoir dressé la liste des opérations en projet ou réalisées, l'auteur conclut à l'existence de plusieurs incertitudes concernant la politique énergétique, les relations Plan/marché, la question de l'unité allemande, la diminution de la dette et la convertibilité de la monnaie. Seule une véritable réforme politique peut espérer engendrer une réforme économique en R.D.A.Unger Helfried. Les premières étapes de la réforme économique en RDA. In: Revue d'études comparatives Est-Ouest, vol. 20, 1989, n°4. pp. 137-146
ChemInform Abstract: Zinc‐Catalyzed Organic Synthesis: C—C, C—N, C—O Bond Formation Reactions
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Pd-Catalyzed Carbonylation of Vinyl Triflates To Afford α,β-Unsaturated Aldehydes, Esters, and Amides under Mild Conditions
No full textAn efficient and
general protocol for the synthesis of α,β-unsaturated
aldehydes, esters, and amides via carbonylation of vinyl triflates
including derivatives of camphor, ketoisophorone, verbenone, and pulegone
was developed. Crucial for these transformations is the use of a specific
palladium catalyst containing a pyridyl-substituted dtbpx-type ligand. This procedure also allows for an easy access of
dicarbonylated products from the corresponding ketones
Ruthenium‐Catalyzed Deuteration of Aromatic Carbonyl Compounds with a Catalytic Transient Directing Group
No full textA novel ruthenium-catalyzed C−H activation methodology for hydrogen isotope exchange of aromatic carbonyl compounds is presented. In the presence of catalytic amounts of specific amine additives, a transient directing group is formed in situ, which directs selective deuteration. A high degree of deuteration is achieved for α-carbonyl and aromatic ortho-positions. In addition, appropriate choice of conditions allows for exclusive labeling of the α-carbonyl position while a procedure for the preparation of merely ortho-deuterated compounds is also reported. This methodology proceeds with good functional group tolerance and can be also applied for deuteration of pharmaceutical drugs. Mechanistic studies reveal a kinetic isotope effect of 2.2, showing that the C−H activation is likely the rate-determining step of the catalytic cycle. Using deuterium oxide as a cheap and convenient source of deuterium, the methodology presents a cost-efficient alternative to state-of-the-art iridium-catalyzed procedures. © 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH Gmb
Ruthenium‐Catalyzed Site‐Selective Trifluoromethylations and (Per)Fluoroalkylations of Anilines and Indoles
No full textIntroducing (per)fluoroalkyl groups into arenes continues to be an interesting, but challenging area in organofluorine chemistry. We herein report an ortho-selective C−H perfluoroalkylation including trifluoromethylations of anilines and indoles without the need of protecting groups using RfI and RfBr as commercially available reagents. The availability and price of the starting materials and the inherent selectivity make this novel methodology attractive for the synthesis of diverse (per)fluoroalkylated building blocks, for example, for bioactive compounds and materials. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA
ChemInform Abstract: Palladium‐Catalyzed Carbonylative Coupling Reactions of Aryl Iodides with Hexamethyldisilane (HMDS) to Benzoyl Silanes.
No full textChemInform Abstract: Palladium‐Catalyzed Carbonylative Coupling of Benzyl Chlorides with Terminal Alkynes to Give 1,4‐Diaryl‐3‐butyn‐2‐ones and Related Furanones.
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