Nucleophilicities of the anions of arylacetonitriles and arylpropionitriles in dimethyl sulfoxide.
The rates of the reactions of the colored para-substituted phenylacetonitrile anions 1a-c and the phenylpropionitrile anions 2a-c with Michael acceptors (3a-u) were determined by UV-vis spectroscopy in DMSO at 20 degrees C. The reactions follow second-order kinetics, and the corresponding rate constants k(2) obey the linear-free-energy relationship log k(2)(20 degrees C) = s(N + E), from which the nucleophile-specific parameters N and s of the carbanions 1a-c and 2a-c have been derived. With nucleophilicity parameters from 19 < N < 29, they are among the most reactive nucleophiles which we have so far parametrized. In DMSO, the nucleophilicity of the tert-butoxide anion is comparable to that of the p-cyanophenylacetonitrile anion 1b.
Kaumanns
Oliver
O
Department Chemie und Biochemie, Ludwig-Maximilians-Universitat Munchen, Butenandtstr. 5-13 (Haus F), 81377 Munchen, Germany.
Appel
Roland
R
Lemek
Tadeusz
T
Seeliger
Florian
F
Mayr
Herbert
H
D000097:Acetonitriles / Q000737:chemistry*; D000838:Anions / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D007189:Indans / Q000138:chemical synthesis / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008314:Malonates / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D011809:Quinones / Q000138:chemical synthesis / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
D000097:Acetonitriles; D000838:Anions; D007189:Indans; D008314:Malonates; D009570:Nitriles; D011809:Quinones; C005557:propionitrile; D004121:Dimethyl Sulfoxide