Tin-Containing Silicates: Identification of a Glycolytic Pathway via 3-Deoxyglucosone

We identify a glycolytic pathway through 3-deoxyglucosone using Lewis acid catalysts resulting in the formation of bio-based monomers.</p

Mild Pd-Catalyzed Aminocarbonylation of (Hetero)Aryl Bromides with a Palladacycle Precatalyst

A palladacyclic precatalyst is employed to cleanly generate a highly active XantPhos-ligated Pd-catalyst. Its use in low temperature aminocarbonylations of (hetero)aryl bromides provides access to a range of challenging products in good to excellent yields with low catalyst loading and only a slight excess of CO. Some products are unattainable by traditional carbonylative coupling.National Institutes of Health (U.S.) (Award GM46059)Danish National Research Foundation (Grant DNRF59)Villum FoundationDanish Council for Independent Researc

Epistemic geographies of climate change: science, space and politics

Anthropogenic climate change has been presented as the archetypal global problem, identified by the slow work of assembling a global knowledge infrastructure, and demanding a concertedly global political response. But this ‘global’ knowledge has distinctive geographies, shaped by histories of exploration and colonialism, by diverse epistemic and material cultures of knowledge-making, and by the often messy processes of linking scientific knowledge to decision-making within different polities. We suggest that understanding of the knowledge politics of climate change may benefit from engagement with literature on the geographies of science. We review work from across the social sciences which resonates with geographers’ interests in the spatialities of scientific knowledge, to build a picture of what we call the epistemic geographies of climate change. Moving from the field site and the computer model to the conference room and international political negotiations, we examine the spatialities of the interactional co-production of knowledge and social order. In so doing, we aim to proffer a new approach to the intersections of space, knowledge and power which can enrich geography’s engagements with the politics of a changing climate

New Directions in Transition Metal Catalyzed Carbonylation Chemistry

Carbon monoxide (CO) represents an important C1-building block for the construction of some of the most fundamental chemical functionalities carrying a carbon–oxygen double bond. Transition metal catalysis plays a key role in promoting such transformations. We have earlier shown that the combination of palladium catalysis with CO releasing molecules and the two-chamber reactor, COware, provides a convenient and safe means for performing traditional Pd-catalyzed carbonylative couplings, as well as being a platform for the discovery of new carbonylation reactions. Furthermore, the method can be adapted to 13C- and 14C-isotope labeling, as well as providing for a suitable setting for developing efficient carbonylation reactions with 11CO. Herein, we provide a short overview of our latest findings in this area with emphasis on carbonylative couplings with fluorinated building blocks, but also discuss our efforts to develop viable Ni-catalyzed carbonylations with aliphatic substrates, which can be performed efficiently under low CO partial pressures

Metal-free halonium mediated acetate shifts of ynamides to access a-halo acrylamides/acrylimides

International audienceA metal-free acetate shift of 3-acetoxy ynamides to access a-iodo, bromo, and chloro acrylamides/acrylimides under very mild conditions is demonstrated. The inherent alkyne activation of ynamides is sufficient to ensure the a-halo acrylamides/acrylimides in high yields without the addition of a catalyst. In all cases high Z-stereoselectivity is observed. © 2011 American Chemical Society

Carbonylative Coupling of Alkyl Zinc Reagents with Benzyl Bromides Catalyzed by a Nickel/NN 2 Pincer Ligand Complex

The reaction between a preassembled Cu-I bimetallic molecular clip with a short intermetallic distance and a series of fully aliphatic cyano-capped ditopic linkers with increasing lengths was investigated. It is shown that, depending on the length of the ditopic linkers, the rational design of unprecedented supramolecular compact metallacycles containing fully aliphatic walls is possible. The specific preorganized molecular arrangement of the molecular clip used favors stabilizing interlinker London dispersion interactions, which allow, as the length of the linkers increases, the selective formation of discrete compact metallacycles at the expense of 1D coordination polymers. The generalizability of this approach was demonstrated by the reaction of fully aliphatic cyano-capped linkers with two other types of preassembled Cu-I bimetallic molecular clips that also had short intermetallic distances