Nucleophilicities of the Anions of Arylacetonitriles and Arylpropionitriles in Dimethyl Sulfoxide

• Published in: Journal of organic chemistry 2009-01, Vol.74 (1), p.75-81
• Main Authors: Kaumanns, Oliver, Appel, Roland, Lemek, Tadeusz, Seeliger, Florian, Mayr, Herbert
• Format: Article
• Language: English
• Subjects: Acetonitriles - chemistry; Anions - chemistry; Chemical reactivity; Chemistry; Dimethyl Sulfoxide - chemistry; Exact sciences and technology; Indans - chemical synthesis; Indans - chemistry; Kinetics; Kinetics and mechanisms; Magnetic Resonance Spectroscopy; Malonates - chemical synthesis; Malonates - chemistry; Molecular Structure; Nitriles - chemistry; Organic chemistry; Quinones - chemical synthesis; Quinones - chemistry; Reactivity and mechanisms; Spectrophotometry, Ultraviolet; Stereoisomerism
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo802241x

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 °C. The reactions follow second-order kinetics, and the corresponding rate constants k 2 obey the linear-free-energy relationship log k 2(20 °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.