The enzymatic β-C-H hydroxylation of the feedstock chemical isobutyric acid has enabled the asymmetric synthesis of a wide variety of polyketides. The analogous transition metal-catalyzed enantioselective β-C-H functionalization of isobutyric acid-derived substrates should provide a versatile method for constructing useful building blocks with enantioenriched α-chiral centers from this abundant C-4 skeleton. However, the desymmetrization of ubiquitous isopropyl moieties by organometallic catalysts has remained an unanswered challenge. Herein, we report the design of chiral mono-protected aminomethyl oxazoline ligands that enable desymmetrization of isopropyl groups via palladium insertion into the C(sp)-H bonds of one of the prochiral methyl groups. We detail the enantioselective β-arylation, -alkenylation, and -alkynylation of isobutyric acid/2-aminoisobutyric acid derivatives, which may serve as a platform for the construction of α-chiral centers.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5480404 | PMC |
| http://dx.doi.org/10.1126/science.aal5175 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Learning, economies of scale, and knowledge gap effects on power generation technology cost improvements.
iScience
January 2025
International Institute for Applied Systems Analysis, Laxenburg, Lower Austria, Austria.
Cost reductions are essential for accelerating clean technology deployment. Because multiple factors influence costs, traditional one-factor learning models, solely relying on cumulative installed capacity as an explanatory variable, may oversimplify cost dynamics. In this study, we disentangle learning and economies of scale effects at unit and project levels and introduce a knowledge gap concept to quantify rapid technological change's impact on costs.
View Article and Find Full Text PDFEnvironmental impacts of restructuring the EU's natural gas supply and consumption: Learnings from the 2022 energy crisis.
iScience
January 2025
Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
In 2022, the European Union put forward the REPowerEU plan in response to Russia's invasion of Ukraine, aiming at enhancing short-term energy security by diversifying imports and reducing natural gas demand while accelerating the deployment of renewable alternatives in the long term. Here, we quantify the life cycle environmental impacts of both REPowerEU's short-term measures, including the controversial extended coal-fired power plant operations, and how the first year of the crisis was managed in practice. We find that the policy measures' impact on greenhouse gas (GHG) emissions would be negligible, although they could have detrimental effects on other environmental categories.
View Article and Find Full Text PDFFOXP2-immunoreactive corticothalamic neurons in neocortical layers 6a and 6b are tightly regulated by neuromodulatory systems.
iScience
January 2025
Institute of Neuroscience and Medicine 10, Research Centre Jülich, 52425 Jülich, Germany.
The / gene, linked to fine motor control in vertebrates, is a potential candidate gene thought to play a prominent role in human language production. It is expressed specifically in a subset of corticothalamic (CT) pyramidal cells (PCs) in layer 6 (L6) of the neocortex. These L6 FOXP2+ PCs project exclusively to the thalamus, with L6a PCs targeting first-order or both first- and higher-order thalamic nuclei, whereas L6b PCs connect only to higher-order nuclei.
View Article and Find Full Text PDFNicotinamide mononucleotide restores impaired metabolism, endothelial cell proliferation and angiogenesis in old sedentary male mice.
iScience
January 2025
Department of Vascular Surgery, Lausanne University Hospital (CHUV), Lausanne, Switzerland.
Aging is accompanied by a decline in neovascularization potential and increased susceptibility to ischemic injury. Here, we confirm the age-related impaired neovascularization following ischemic leg injury and impaired angiogenesis. The age-related deficits in angiogenesis arose primarily from diminished EC proliferation capacity, but not migration or VEGF sensitivity.
View Article and Find Full Text PDFIFN-γ licenses normal and pathogenic ALPK1/TIFA pathway in human monocytes.
iScience
January 2025
CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, University Lyon, F-69007 Lyon, France.
Alpha-kinase 1 (ALPK1) is an immune receptor sensing the bacterial nucleotide sugar ADP-heptose. ALPK1 phosphorylates TIFA leading to its oligomerization and downstream NF-κB activation. Specific mutations in are associated with an autoinflammatory syndrome termed ROSAH and with spiradenoma (skin cancers with sweat gland differentiation).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!