A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C−O bond cleavage is described for the first time. A wide ...range of aryl triflates as well as aryl mesylates, tosylates and alkenyl triflates afford the corresponding products in good to excellent yields.
A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C−O bond cleavage is described. A variety of aryl triflates, mesylates, tosylates, and alkenyl triflates react with α‐amino acids to afford the corresponding aminomethylated products in good to excellent yields.
Tetrahydroisoquinolines and tetrahydrobenzazepines were prepared by acid‐promoted ring contraction of cyclic ureas, which were themselves formed by ring expansion of indolines and ...tetrahydroquinolines. The consequent overall one‐carbon insertion reaction gives these 6‐ and 7‐membered heterocyclic scaffolds in three steps from readily available precursors. Other ring sizes may be formed by an alternative elimination reaction of bicyclic structures. Scalability of the method was demonstrated by operating it in a flow system.
More and less: Acid‐induced ring contraction of medium‐ring ureas provides access to valuable bioactive scaffolds such as tetrahydroisoquinolines and tetrahydrobenzazepines. The cyclic ureas are first formed by ring expansion of indolines and tetrahydroquinolines, and the consequent overall one‐carbon insertion reaction gives these 6‐ and 7‐membered heterocyclic scaffolds in three steps from readily available precursors.
Life cycle analysis of the GRAND experiment Vargas-Ibáñez, Leidy T.; Kotera, Kumiko; Blanchard, Odile ...
Astroparticle physics,
February 2024, 2024-02-00, 2024-02, Letnik:
155
Journal Article
Recenzirano
Odprti dostop
The goal of our study is to assess the environmental impact of the installation and use of the Giant Radio Array for Neutrino Detection (GRAND) prototype detection units, based on the life cycle ...assessment (LCA) methodology, and to propose recommendations that contribute to reduce the environmental impacts of the project at later stages. The functional unit, namely the quantified description of the studied system and of the performance requirements it fulfils, is to detect radio signals autonomously during 20 years, with 300 detection units deployed over 200km2 in the Gansu province in China (corresponding to the prototype GRANDProto300). We consider four main phases: the extraction of the materials and the production of the detection units (upstream phases), the use and the end-of-life phases (downstream phases), with transportation between each step. An inventory analysis is performed for the seven components of each detection unit, based on transparent assumptions. Most of the inventory data are taken from the Idemat2021 database (Industrial Design & Engineering Materials). Our results show that the components with the highest environmental impact are the antenna structure and the battery. The most pregnant indicators are ‘resource use’, mineral and metals’; ‘resource use, fossils’; ‘ionizing radiation, human health’; ‘climate change’; and ‘acidification’. Therefore, the actions that we recommend in the first place aim at reducing the impact of these components. They include limiting the mass of the raw material used in the antenna, changing the alloy of the antenna, considering another type of battery with an extended useful life, and the use of recycled materials for construction. As a pioneering study applying the LCA methodology to a large-scale physics experiment, this work can serve as a basis for future assessments by other collaborations.
In highly competitive research environments, the ability to access more complex structural spaces efficiently is a predictor of a company's ability to generate novel IP-protected small molecule ...candidates with adequate properties, hence filling their development pipelines. SpiroChem
is consistently developing new synthetic methodologies and strategies to access complex molecular structure, thereby facilitating and accelerating small molecule drug discovery. Pushing the limits of what are perceived as complex molecular structures allows SpiroChem and its clients
to unleash creativity and explore meaningful chemical spaces, which are under-exploited sources of novel active molecules. In this article, we explain how we differentiated ourselves in a globalized R&D environment and we provide several snapshots of how efficient methodologies can generate
complex structures, rapidly.
Herein we report a workflow coupling photoredox-nickel dual-catalyzed
-arylation reactions to benchtop analysis for the efficient generation of fragment-based libraries. Technological advances in ...photoreactor design facilitated reliable and reproducible experimentation. Knowledge on the reactivity under previously reported reaction conditions of spirocyclic and strained heterocyclic building blocks, viewed as chemistry informers, could thus be rapidly accessed, identifying privileged or challenging scaffolds and paving the way for further exploration.
A continuous flow oxidative photocyclization of stilbene derivatives has been developed which allows the scalable synthesis of backbone functionalized phenanthrenes and helicenes of various sizes in ...good yields.
Trifluoromethylation of olefins and (hetero)aromatics with sodium triflinate as CF3 source and readily accessible benzophenone derivatives as photosensitisers has been developed in batch and flow. ...The use of an iridium-based photocatalyst enables the trifluoromethylation to proceed under visible light irradiation.
Carbon-carbon double bond (C=C) formation is a crucial transformation in organic chemistry. Visible-light photoredox catalysis provides economical and sustainable opportunities for the development of ...novel and peculiar organic reactions. Here we report a method for the olefination of alkyl halides with aldehydes by visible-light photoredox catalysis using triphenylphosphine as a reductive quencher (103 examples). This transformation accommodates a variety of aldehydes including paraformaldehyde; aqueous formaldehyde; 2,2,2-trifluoroacetaldehyde monohydrate; 2,2,2-trifluoro-1-methoxyethanol; and other common aldehydes. The present method exhibits several advantages, including operational simplicity, mild reaction conditions, wide functional group tolerance, and amenability to gram-scale synthesis. We anticipate that it will be widely used in the synthesis of organic molecules, natural products, biological molecules, and polymers.
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•General olefination of benzyl halides and bromoacetamides with aldehydes•Operational simplicity and mild conditions under visible-light photoredox catalysis•Wide substrate scope and high efficiency•Amenability to gram-scale synthesis
Chemistry; Catalysis; Organic Chemistry
A tin‐ and halide‐free, visible‐light photoredox‐catalyzed Giese reaction was developed. Primary and secondary α‐amino radicals were generated readily from amino acids in the presence of catalytic ...amounts of an iridium photocatalyst. The reactivity of the α‐amino radicals has been evaluated for the functionalization of a variety of activated olefins.
Easy CO2upling! A tin‐ and halide‐free, visible‐light photoredox‐catalyzed Giese reaction was developed. Primary and secondary α‐amino radicals were generated from amino acids in the presence of catalytic amounts of an iridium photocatalyst and catalytic amounts of base. These radicals added readily onto activated olefins, giving CO2 as sole by‐product.
A tin- and halide-free, visible-light photoredox-catalyzed Giese reaction was developed. Primary and secondary alpha-amino radicals were generated readily from amino acids in the presence of ...catalytic amounts of an iridium photocatalyst. The reactivity of the alpha-amino radicals has been evaluated for the functionalization of a variety of activated olefins.
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