ISSN:
0894-3230
Schlagwort(e):
Organic Chemistry
;
Physical Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
4-O2NC6H4OCH2CH2NHPh undergoes clean base-catalyzed Smiles photorearrangement to 4-O2NC6H4N(Ph)CH2CH2OH in dimethyl sulfoxide-water (25:75). A linear plot of φ-1 vs [OH-]-1 indicated that the limiting quantum yield at high [OH-] is 0·12 and that uncatalyzed photorearrangement does not occur. Rate constants for the deprotonation step were determined for a variety of bases having conjugate acid pKa values in the range 5-10. When plotted according to the Brønsted Catalysis Law, these data gave a non-linear plot approaching slopes of zero and unity above and below a pKa of 6-7. This indicates that the proton-donating intermediate in this photo-Smiles rearrangement is the zwitterion diradical (pKa ≈ 7) rather than the Meisenheimer complex (pKa ≈ 2).
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/poc.610020209
