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Ligand-controlled divergent dehydrogenative reactions of carboxylic acids via C-H activation.
- Source :
-
Science (New York, N.Y.) [Science] 2021 Dec 03; Vol. 374 (6572), pp. 1281-1285. Date of Electronic Publication: 2021 Nov 11. - Publication Year :
- 2021
-
Abstract
- Dehydrogenative transformations of alkyl chains to alkenes through methylene carbon-hydrogen (C–H) activation remain a substantial challenge. We report two classes of pyridine-pyridone ligands that enable divergent dehydrogenation reactions through palladium-catalyzed β-methylene C–H activation of carboxylic acids, leading to the direct syntheses of α,β-unsaturated carboxylic acids or γ-alkylidene butenolides. The directed nature of this pair of reactions allows chemoselective dehydrogenation of carboxylic acids in the presence of other enolizable functionalities such as ketones, providing chemoselectivity that is not possible by means of existing carbonyl desaturation protocols. Product inhibition is overcome through ligand-promoted preferential activation of C(sp <superscript>3</superscript> )–H bonds rather than C(sp <superscript>2</superscript> )–H bonds or a sequence of dehydrogenation and vinyl C–H alkynylation. The dehydrogenation reaction is compatible with molecular oxygen as the terminal oxidant.
- Subjects :
- 4-Butyrolactone analogs & derivatives
4-Butyrolactone chemical synthesis
4-Butyrolactone chemistry
Carboxylic Acids chemical synthesis
Catalysis
Chemical Phenomena
Hydrogen Bonding
Ligands
Molecular Structure
Oxidation-Reduction
Oxygen chemistry
Palladium chemistry
Pyridines chemistry
Pyridones chemistry
Carbon chemistry
Carboxylic Acids chemistry
Chemistry Techniques, Synthetic
Hydrogen chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1095-9203
- Volume :
- 374
- Issue :
- 6572
- Database :
- MEDLINE
- Journal :
- Science (New York, N.Y.)
- Publication Type :
- Academic Journal
- Accession number :
- 34762490
- Full Text :
- https://doi.org/10.1126/science.abl3939