HIGHLY REACTIVE PLATINUM(0) CARBENE INTERMEDIATES IN THE REACTIONS OF DIAZO-COMPOUNDS - A FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRIC STUDY

The reaction of [Pt(CH2=CH2)(PPh(3))(2)] (1) with N(2)CHCO(2)Et, carried out directly in the FAB matrix and monitored by MS, leads to molecular ions corresponding to the species [Pt(N2C(H)CO(2)Et)(PPh(3))(2)], [Pt{C(H)CO(2)Et}(PPh(3))(2)], and [Pt{C(H)CO(2)Et}(PPh(3))2]2, which are involved as intermediaries in the formation of the final fumarate Pt(0) derivative [Pt{trans-C(H)CO2-Et=C(H)CO(2)Et}(PPh(3))(2)]. Chemical evidence of the intermediacy of a Pt(0) carbene stems from the fact that 1 is active in the cyclopropanation of styrene in the presence of N(2)CHCO(2)Et.