Barton Decarboxylation refers to a radical reaction in which a carboxylic acid is first converted into a thiohydroxamate ester (also known as a Barton ester), and then thermally decomposed in the presence of a radical initiator and a suitable hydrogen donor to yield the decarboxylated product. The reaction is named after Sir Derek Barton (1918–1998), a British chemist and Nobel Laureate who developed it.
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Reagents: 1-Hydroxy-2(1H)-pyridinethione, DCC, DMAP, AIBN, benzene (PhH)
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Reactant: Carboxylic acid
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Product: Decarboxylated product
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Reaction Type: Radical reaction
Experimental Tips:
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In the first step, converting the carboxylic acid to the corresponding acid chloride can improve reactivity.
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In organic synthesis, this reaction can be used to install a carboxyl group at a specific position and then remove it via Barton decarboxylation.
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Trialkyltin hydrides used in this reaction are neurotoxic; proper safety precautions should be taken.
Reaction Mechanism:
Mechanism of the Barton Decarboxylation Reaction
Original Publications:
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Barton, D. H. R.; Crich, D. J. Chem. Soc., Chem. Commun., 1983, 939–941.
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Barton, D. H. R.; Crich, D.; Motherwell, W. B. Tetrahedron Letters, 1983, 24 (25), 4979–4982.
Key References:
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Nickel-Catalyzed Barton Decarboxylation and Giese Reactions: A Practical Take on Classic Transforms, Angew. Chemie, 2017, 56 (1), 260–265.
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Chloroform as a Hydrogen Atom Donor in Barton Reductive Decarboxylation Reactions, J. Org. Chem., 2013, 78 (13), 6677–6687.