N‑Acyl-glutarimides: Resonance and Proton Affinities of Rotationally-Inverted Twisted Amides Relevant to N–C(O) Cross-Coupling

Resonance energies and proton affinities of N-acyl-glutarimides, compared with related twisted acyclic amides of relevance to N–C­(O) cross-coupling, are reported. The data demonstrate that amidic resonance in N-acyl-glutarimides practically disappears (E R < 2.8 kcal/mol), while, intriguingly, t...

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Bibliographic Details
Published in:Organic letters 2018-03, Vol.20 (5), p.1342-1345
Main Authors: Szostak, Roman, Szostak, Michal
Format: Article
Language:English
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Summary:Resonance energies and proton affinities of N-acyl-glutarimides, compared with related twisted acyclic amides of relevance to N–C­(O) cross-coupling, are reported. The data demonstrate that amidic resonance in N-acyl-glutarimides practically disappears (E R < 2.8 kcal/mol), while, intriguingly, these amides favor O-protonation despite significant twist. In some cases, N-acyl-glutarimides undergo intramolecular N- to O-acyl migration, indicative of high capacity as acylating reagents. The understanding provided for the high reactivity of N-acyl-glutarimides should facilitate the development of a broadly general N–C­(O) amide activation platform.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.8b00086