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Related Reactions
Barton-McCombie Reaction

Barton Decarboxylation

The radical decarboxylation of a Barton ester proceeds to the corresponding alkane after treatment with tributyltin hydride or t-butylmercaptan:

An alternative possibility is the introduction of a substituent by reaction with a suitable radical trapping agent:

Mechanism of the Barton Decarboxylation

The initiation of the Barton Decarboxylation ( Bu3Sn-H -> Bu3Sn. ) is effected with a radical initiator, and as with the Barton-McCombie Deoxygenation, the driving force for the reaction itself is the formation of the stable S-Sn bond.

In addition, Barton esters can also be cleaved photolytically or thermally:

If an excess of a suitable radical trapping agent is present in the reaction medium, substitution will occur; otherwise, radical recombination takes place to give the pyridyl sulfide:

The Barton Decarboxylation offers several options for the introduction of substituents - some examples are shown below:

J. Zhu, A. J. H. Klunder, B. Zwanenburg, Tetrahedron, 1995, 51, 5099-5116.

Recent Literature

Synthesis of 6-functionalized tricyclodecadienones using Barton's radical decarboxylation reaction. Generation of tricyclo[,6]decatrienone, a norbornene annulated cyclopentadienone
J. Zhu, A. J. H. Klunder, B. Zwanenburg, Tetrahedron, 1995, 51, 5099-5116.

Synthesis of (-)-Ilimaquinone via a Radical Decarboxylation and Quinone Addition Reaction
T. Ling, E. Poupon, E. J. Rueden, E. A. Theadorakis, Org. Lett., 2002, 4, 819-822.