The α-Effect in Reactions of sp-Hybridized Carbon Atom:  Michael-Type Reactions of 1-Aryl-2-propyn-1-ones with Primary Amines

• Published in: Journal of organic chemistry Vol. 70; no. 19; pp. 7530 - 7536
• Main Authors: Um, Ik-Hwan, Lee, Eun-Ju, Seok, Jin-Ah, Kim, Kyung-Hee
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 16.09.2005
• Subjects: Chemistry; Exact sciences and technology; Kinetics and mechanisms; Organic chemistry; Reactivity and mechanisms; Michael addition; Substituent effect; Acetylenic compound; Ketone; Kinetic isotope effect; Alpha effect; Aromatic compound; Alkalinity; Kinetics; Rate constant; Hydrazine; Primary amine; Hydrogen bond; Nucleophile

Second-order rate constants (k N) have been measured for the Michael-type reaction of 1-(X-substituted phenyl)-2-propyn-1-ones (2a−f) with a series of primary amines in H2O at 25.0 ± 0.1 °C. A linear Brønsted-type plot with a small βnuc value (βnuc = 0.30) has been obtained for the reactions of 1-ph...