Lewis base-assisted hydride-carbyne to olefin transformation versus carbene formation

Abstract

Complex [OsH(η5-C5H5)(≡C-CH2Ph)(P iPr3)]BF4 (1) reacts with KBr in tetrahydrofuran to give the π-olefin derivative OsBr(η5-C5H5)(η2-CH2 =CHPh)(PiPr3), which has been characterized by X-ray diffraction analysis. Similarly, the reaction of [OsH(η5-C5H5)(≡C-CD2Ph)(P iPr3)]BF4 (1-d2) with KBr leads to the π-dideuterated-olefin complex. On the basis of the deuterium distribution in this complex and the previously reported P(OMe)3-assisted hydride-carbyne to carbene transformation, the mechanism of the Br-assisted hydride-carbyne to olefin transformation is discussed.