The triethylamine-catalyzed addition reactions of benzenethiol to 2-cyclopenten-1-one and its 2- and 3-methyl derivatives have been found to be appreciably reversible in chloroform solution. Rates and equilibria have been carefully measured at 25 °C in order to assess the negative influence on addition exerted by methyl groups substituted on the carbon-carbon double bond. 2-Methyl-2- cyclopenten-1-one has been found to react with benzenethiol under kinetic control to give the cis adduct as the sole detectable product in a highly stereoselective anti addition process. However, on prolonged reaction times the system slowly evolved toward a new state of equilibrium in which the more stable trans adduct, derived from a syn addition mode, was the predominant isomer.
Rates and Equilibria of the Michael-type Addition of Benzenethiol to 2-Cyclopenten-1-ones / VAN AXEL CASTELLI, V; Bernardi, F; DALLA CORT, Antonella; Mandolini, Luigi; Rossi, I; L., Schiaffino. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 64:(1999), pp. 8122-8126. [10.1021/jo9906882]
Rates and Equilibria of the Michael-type Addition of Benzenethiol to 2-Cyclopenten-1-ones
DALLA CORT, Antonella;MANDOLINI, Luigi;
1999
Abstract
The triethylamine-catalyzed addition reactions of benzenethiol to 2-cyclopenten-1-one and its 2- and 3-methyl derivatives have been found to be appreciably reversible in chloroform solution. Rates and equilibria have been carefully measured at 25 °C in order to assess the negative influence on addition exerted by methyl groups substituted on the carbon-carbon double bond. 2-Methyl-2- cyclopenten-1-one has been found to react with benzenethiol under kinetic control to give the cis adduct as the sole detectable product in a highly stereoselective anti addition process. However, on prolonged reaction times the system slowly evolved toward a new state of equilibrium in which the more stable trans adduct, derived from a syn addition mode, was the predominant isomer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
