Are α-centered peptide radicals stabilized by a capto-dative effect?

The kinetics of the thermal C-C-cleavage reaction of the dimer of sarcosine anhydride 5 has been investigated between 295 and 333 °C in mesitylene. From the temperature dependence and from the release of strain on dissociation the cyclic α-peptide radical 6 was calculated to have a radical stabiliza...

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Bibliographic Details
Published in:Tetrahedron letters 1997-11, Vol.38 (44), p.7721-7724
Main Authors: Brocks, Jochen J., Welle, Frank M., Beckhaus, Hans-Dieter, Rüchardt, Christoph
Format: Article
Language:English
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Summary:The kinetics of the thermal C-C-cleavage reaction of the dimer of sarcosine anhydride 5 has been investigated between 295 and 333 °C in mesitylene. From the temperature dependence and from the release of strain on dissociation the cyclic α-peptide radical 6 was calculated to have a radical stabilization enthalpy (RSE) of −6.3 ± 1.3 kcal/mol thus indicating the absence of a synergistic capto-dative effect. From ΔH‡ of the dissociation of 5 and from the release of strain on dissociation the cyclic α-peptide radical 6 was calculated to have a radical stabilization enthalpy (RSE) of −6.3 ± 1.3 kcal/mol indicating the absence of a synergistic capto-dative effect
ISSN:0040-4039
1873-3581
DOI:10.1016/S0040-4039(97)10085-5