A novel stereocontrolled synthesis of cyclopropyl-substituted a, β-unsaturated esters: Palladium catalyzed cross-coupling of cyclopropylboronic acids with bromoacrylates

Abstract

A novel method of stereocontrolled preparing some cyclopropyl substituted α,β-unsaturated esters is described, based upon the palladium catalyzed cross-coupling reaction of bromoacrylates with trans-2-alkyl(aryl)cyclopropylboronic acids. It was found that using toluene as a solvent and in the presence of K3PO4•3H2O and catalytic amount of Pd(PPh3)4 the bromoacrylates could readily take part in the cross-coupling reaction with cyclopropylboronic acids at 100°C, giving corresponding stereodefined cyclopropyl substituted α,β-unsaturated esters in good to excellent yields.