Fr. Kreissl et al., COMPETING M=(CARBONYL) AND M=C(CARBENE) BONDS - CYCLOADDITION TO THE METAL-C(CARBONYL) BOND IN ETA(2)-THIOCARBENE COMPLEXES, Angewandte Chemie, International Edition in English, 32(8), 1993, pp. 1152-1154
New light on the reactivity of M=C and M=C=O double bonds in eta2-thio
carbene complexes has been shed by the cycloaddition reaction of 1 wit
h thio- and selenourea. In these reactions not the M=C(carbene) bond,
but for the first time the M=C(CO) bond is attacked, leading to the fo
rmation of the spirocyclic compounds 2 (X=S) and 3 (X=Se).