I wonder how the π delocalization of guanidino groups affects the reactivity of the terminal nitrogens with respect to alkyl halides compared to, say, primary amines?

  • $\begingroup$ Doesn't delocalization prevent reactivity with alkyl halides? For instance once amides are formed from acyl halides, why are there no further substitution on the newly introduced NH2 if there are halides nearby? $\endgroup$
    – Mowgli
    Commented Aug 11, 2022 at 17:45
  • 1
    $\begingroup$ Well, yes, they do react. I guess imino position is activated, while amine groups deactivated. That clearly shows in guanidine's very high basicity. $\endgroup$
    – Mithoron
    Commented Aug 11, 2022 at 17:46
  • 2
    $\begingroup$ Yes they alkylate, example pubs.acs.org/doi/abs/10.1021/jo0265535 $\endgroup$
    – Waylander
    Commented Aug 11, 2022 at 20:20
  • $\begingroup$ @Waylander in this paper they use protected guanidines so they are able to deprotonate an acidic N-carbamate hydrogen; I assume that same approach wouldn't work with a naked (basic) guanidine? $\endgroup$
    – Mowgli
    Commented Aug 12, 2022 at 21:35
  • $\begingroup$ @Mowgli I don't know, but if you can access this review it may tell you thieme-connect.com/products/ejournals/abstract/10.1055/… $\endgroup$
    – Waylander
    Commented Aug 13, 2022 at 6:34


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