Recent Advances in Electrophilic CF3-Transfer Using Hypervalent Iodine(III) Reagents

The development of new methodologies for an efficient introduction of CF3 groups into complex molecules constitutes one of the most challenging tasks of modern organic chemistry. Recently, we reported the access to a new class of electrophilic CF3-transfer reagents based on hypervalent iodine. The versatile application of these reagents to C-centred nucleophiles, such as ?-keto esters, silyl enol ethers and ?-nitro esters, as well as to thiols and primary and secondary phosphines is described. Experiments with phenols afforded corresponding trifluomethylethers in very low yields

Copper-Catalyzed Trifluoromethylation of Unactivated Olefins

Activating the inactive: A copper-catalyzed allylic trifluoromethylation of unactivated terminal olefins proceeds under mild conditions to produce linear allylic trifluoromethylated products with high E/Z selectivity (see scheme). The reaction can be applied to a range of substrates bearing numerous functional groups. Furthermore, the reaction is scalable and amenable to a benchtop setup.National Institutes of Health (U.S.) (GM46059)National Institutes of Health (U.S.) (Postdoctoral Fellowship F32GM093532)National Science Foundation (U.S.) (Grant ACHE-9808061)National Science Foundation (U.S.) (Grant DBI-9729592)National Institutes of Health (U.S.) (Grant 1S10RR13886-01

Structural Reevaluation of the Electrophilic Hypervalent Iodine Reagent for Trifluoromethylthiolation Supported by the Crystalline Sponge Method for X-ray Analysis

Hypervalent iodine λ[superscript 3]-benziodoxoles are common electrophilic transfer reagents known for their enhanced stability compared to their non-cyclic analogues. Herein we present data showing that chlorobenziodoxole reacts with two different thiolate nucleophiles (thiocyanate and trifluoromethylthiolate), resulting in the formation of stable thioperoxy complexes rather than the expected benziodoxole derivatives. We further report a revised structure for the earlier described electrophilic trifluoromethylthiolation reagent (1), which was previously believed to contain the benziodoxole framework. Our findings, which are based on a combination of analytical techniques, including the recently introduced crystalline sponge method for X-ray analysis, unambiguously demonstrate that 1 is a thioperoxy compound both in solution and the solid state.National Institutes of Health (U.S.) (Award GM58160

Electrophilic fluorination using a hypervalent iodine reagent derived from fluoride

The air and moisture stable fluoroiodane 8, readily prepared on a 6 g scale by nucleophilic fluorination of the hydroxyiodane 7 with TREAT-HF, has been used as an electrophilic fluorinating reagent for the first time to monofluorinate 1,3-ketoesters and difluorinate 1,3-diketones in good isolated yields

Palladium–mediated organofluorine chemistry

Producción CientíficaThe substitution of fluorine for hydrogen in a molecule may result in profound changes in its properties and behaviour. Fluorine does not introduce special steric constraints since the F atom has a small size. However, the changes in bond polarity and the possibility of forming hydrogen bonds with other hydrogen donor fragments in the same or other molecules, may change the solubility and physical properties of the fluorinated compound when compared to the non-fluorinated one. Fluorine forms strong bonds to other elements and this ensures a good chemical stability. Altogether, fluorinated compounds are very attractive in materials chemistry and in medicinal chemistry, where many biologically active molecules and pharmaceuticals do contain fluorine in their structure and this has been shown to be essential for their activityJunta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA256U13

Die Entwicklung des Einzelhandels und der Shopping Center - Symbiose oder Konkurrenz? - Dargestellt an ausgewählten Beispielen

Das Ziel dieser Bachelorarbeit ist die Herausarbeitung von Faktoren, die verschiedene Wege der gelungenen Integration eines Shopping-Centers in die Innenstadt aufzeigen. Dabei liegt der Fokus auf Faktoren, die eine Symbiose zwischen den Akteuren Stadt und Shopping-Center fördern. Anhand festgelegter Kriterien werden ausgewählte Center systematisch bewertet und die sich daraus ergebenden Auswirkungen auf den Einzelhandel analysiert