Kumada Coupling of Aryl and Vinyl Tosylates under Mild Conditions

Abstract

Aryl tosylates are cheap, stable and easily available derivatives of phenols and relative alkenyl tosylates can be readily prepared from ketones. Therefore, their use as electrophiles in cross-coupling reactions is highly advantageous. Although there are some publications on the Kumada coupling between aryl tosylates and Grignard reagents, the authors’ approach offers a new mild, versatile and practical synthetic protocol. The catalyst (Josiphos, 1) is commercially available. The amount of the Grignard reagent used is almost always nearly equimolar, and both aryl-, alkenyl-, cycloalkyl- and alkylmagnesium halides are shown to react smoothly.