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Nitronate Anion Recognition and Modulation of Ambident Reactivity by Hydrogen‐Bonding Receptors
Author(s) -
Linton Brian R.,
Goodman M. Scott,
Hamilton Andrew D.
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20000703)6:13<2449::aid-chem2449>3.0.co;2-9
Subject(s) - nitronate , chemistry , alkylation , reactivity (psychology) , thiourea , medicinal chemistry , hydrogen bond , stereochemistry , organic chemistry , catalysis , nitro , molecule , medicine , alkyl , alternative medicine , pathology
Nitronate anions were shown to form complexes in DMSO with hydrogen‐bonding receptors such as 1,3‐dimethylthiourea 1 ( K a =120 M −1 ) and bicyclic guanidinium 2 ( K a =3200 M −1 ). A ditopic bis‐thiourea exhibited increased association with substrates, that contained either two nitronates ( K a =7000 M −1 ) or a combination of nitronate and carboxylate ( K a =7200 M −1 ). Complexation of nitronate resulted in a change in the ambident reactivity during alkylation with p ‐nitrobenzyl bromide. The predominant reaction pathway was shifted from oxygen alkylation to carbon alkylation as receptor binding strength increased. Kinetic analysis indicated an overall inhibition of nitronate reactivity, and this suggests that greater suppression of the oxygen pathway allows carbon alkylation to predominate.