C-O bond formation in reactions of olefins with oxygen is a long standing challenge in chemistry for which the very complicated-sometimes controversial-mechanistic panorama slows down the design of catalysts for oxygenations. In this regard, the mechanistic details of the oxidation of the complex [Rh(cod)(Ph N )] (1) (cod=1,5-cyclooctadiene) with oxygen to the unique 2-rhodaoxetane compound [{Rh(OC H )(Ph N )} ] (2) has been investigated by DFT calculations. The results of this study provide evidences for a novel bimetallic mechanism in which two rhodium atoms redistribute the four electrons involved in the cleavage of the O=O bond. Furthermore, both oxygen atoms are used to create two new C-O bonds in a controlled fashion with 100 % atom economy. The key intermediates that we have found in this process are a mononuclear open-shell triplet superoxo compound, an open-shell singlet "μ-(peroxo)" derivative, and a closed-shell singlet "bis(μ-oxo)" complex. Some of the findings are used to predict the reactions of Rh complexes with oxygen, exemplified by that of the complex [Rh(cod)(OnapyMe )] (3). Starting from 3, [{Rh(OC H )(OnapyMe )} ] (4) has been prepared and characterized, which represents the second example of a 2-rhodaoxetane compound coming from an oxygenation reaction with oxygen.
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http://dx.doi.org/10.1002/chem.201605959 | DOI Listing |
Molecules
December 2024
School of Chemistry and Chemical Engineering, Guangxi Minzu University, Nanning 530006, China.
The selective depolymerization of β-O-4 lignin models into high-value aromatic monomers using photocatalysis presents both significant opportunities and challenges. Photocatalysts often face issues such as high photogenerated carrier recombination rates and limited operational lifetimes. This study introduces S doping to modulate the surface interface of BiOCl (BOC) nanosheets, enhancing C-O bond cleavage efficiency in β-O-4 lignin models under visible light at ambient temperatures.
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November 2024
Department of Bioprocess Development, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications (SRTA-City), New Borg El Arab City 21934, Egypt.
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View Article and Find Full Text PDFNat Commun
January 2025
College of Chemistry, Central China Normal University (CCNU), Wuhan, Hubei, PR China.
C-C and C-X bond forming reactions are essential tools in organic synthesis, constantly revolutionizing human life. Among the key methods for constructing new chemical bonds are nucleophilic addition reactions involving imines. However, the inherent challenges in synthesizing and storing imines have stimulated interest in designing stable precursors, which generates imines in situ during the reaction.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University, Xinxiang, Henan453007,China.
Borenium ions have attracted significant attention in organic transformations due to their strong Lewis acidity. The reported borenium ions are often stabilized by sterically demanding substituents and strong coordination bonds. Herein, we have synthesized a small steric borenium-equivalent NHBHOTf and subjected it to the exhaustive reduction of a carboxylic functional group to a methyl group, which shows broad functional group tolerance.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
A variety of α-arylated sulfoxonium ylides could be facilely synthesized in modest to high yields through α-arylation of sulfoxonium ylides with aryl fluorosulfates C-O bond functionalization under palladium catalysis. Reactions using readily available and bench-stable aryl fluorosulfates as effective and appealing arylating agents showed both good substrate scope and broad functionality tolerance. Important functional groups such as nitro, cyano, formyl, acetyl, methoxycarbonyl, trifluoromethoxy, fluoro, and chloro embedded in substrates remained intact during the course of the reaction, and could be subjected to downstream modification.
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