Whereas [4 + 2] cycloadditions are among the most powerful tools in the chemist's synthetic arsenal, controlling reactivity and selectivity of [6 + 4] cycloadditions has proven to be extremely challenging. Such transformations, especially if compatible with simple hydrocarbon-based substrates, could ultimately provide a general approach to highly valuable and otherwise difficult to access 10-membered rings. We report here that highly acidic and confined imidodiphosphorimidate catalysts do not catalyze this reaction under homogeneous conditions. Notably, however, they can spontaneously precipitate an insoluble and double helix-shaped noncovalent organic framework, which acts as a distinctively reactive and stereoselective catalyst of [6 + 4] cycloadditions of simple dienes with tropone.
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http://dx.doi.org/10.1126/science.adp1127 | DOI Listing |
ChemMedChem
January 2025
Central University of Haryana, Chemistry, Academic Block-1, Jant-Pali, 123 031, Mahendergarh, INDIA.
Multicomponent reactions have long been recognized as some of the most versatile tools in organic chemistry, with extensive applications in biomedical science and the pharmaceutical industry. In this study, we explored the potential of the Passerini reaction by designing and synthesizing new low molecular mass gelators that can serve as novel formulations for prolonged anesthesia. These gelators address critical issues like poor solubility, low bioavailability, and short plasma half-life, all of which hinder therapeutic efficacy.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
RIKEN: Rikagaku Kenkyujo, Center for Sustainable Resource Science, 2-1 Hirosawa, 351-0198, Wako, JAPAN.
Transition-metal-catalyzed selective and efficient activation of an inert C-H bond in an organic substrate is of importance for the development of streamlined synthetic methodologies. An attractive approach is the design of a metal catalyst capable of recognizing an organic substrate through noncovalent interactions to control reactivity and selectivity. We report here a spirobipyridine ligand that bears a hydroxy group that recognizes pyridine and quinoline substrates through hydrogen bonding, and in combination with an iridium catalyst enables site-selective C-H borylation.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Coordination Chemistry, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
Chiral binaphthols (BINOL)-metal combinations serve as powerful catalysts in asymmetric synthesis. Their chiral induction mode, however, typically relies on multifarious non-covalent interactions between the substrate and the BINOL ligand. In this work, we demonstrate that the chiral-at-metal stereoinduction mode could serve as an alternative mechanism for BINOL-metal catalysis, based on mechanistic studies of BINOL-aluminum-catalyzed asymmetric hydroboration of heteroaryl ketones.
View Article and Find Full Text PDFChemistry
January 2025
Institute of Chemical Research of Catalonia: Institut Catala d'Investigacio Quimica, -, Av. Països Catalans 16, 43007, Tarragona, SPAIN.
Noncovalent interactions are present in numerous synthetic and biological systems, playing an essential role in vital processes for life such as stabilization of proteins' structures or reversible binding in substrate-receptor complexes. Their study is relevant, but it presents challenges due to its inherent weak nature. In this context, molecular balances (MBs) are one of the most efficient physical organic chemistry tools to quantify noncovalent interactions, bringing beneficial knowledge regarding their nature and strength.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Key Laboratory of Functional Polymer Materials (Ministry of Education), Frontiers Science Center for New Organic Matter, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China.
On the one hand, nature utilizes hierarchical assemblies to create complex biological binding pockets, enabling ultrastrong recognition toward substrates in aqueous solutions. On the other hand, chemists have been fervently pursuing high-affinity recognition by constructing covalently well-preorganized stereoelectronic cavities. The potential of noncovalent assembly, however, for enhancing molecular recognition has long been underestimated.
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