Catalytic dehydrosilylation of 1-trimethylsilyloxycyclopent-1-ene to cyclopent-2-enone with oxygen over palladium supported on silica

Abstract

1-Trimethylsilyloxycyclopent-1-ene has been catalytically converted into cyclpent-2-enone through its reaction with oxygen in the presence of palladium(0) supported on silica. The choice of solvent is crucial, N-methyl-2-pyrrolidone being the most effective solvent. Thus, palladium (3.9wt%) supported on silica gave a 90.1% yield of cyclopent-2-enone and a 99.2% selectivity at 333 K for 24 h. The catalyst can be also utilized in the dehydrosilylation of 1-trimethylsilyloxycyclohex-1-ene into cyclohex-2-enone. This catalytic reaction offers a convenient and useful method for the synthesis of α,β-unsaturated ketones such as cyclopent-2-enone, since molecular oxygen can be used as a convenient oxidant. The reaction mechanism has been proposed on the basis of mass spectral measurements in the dehydrosilylation of 1-trimethylsilyloxycyclopent-1-ene with ¹⁸O₂ over palladium(0) supported on silica.