Reactivity of the Amido Complex [Re(NH<i>p</i>Tol)(CO)<sub>3</sub>(bipy)] toward Neutral Organic Electrophiles

The amido complex [Re(NH<i>p</i>Tol)(CO)<sub>3</sub>(bipy)] (<b>1</b>) reacts with <i>p</i>TolNCS and with Ph<sub>2</sub>CCO giving the products of the insertion of these heterocumulenes into the Re−N and N−H bonds, the complexes [Re{SC(N<i>p</i>Tol)(NH<i>p</i>Tol)}(CO)<sub>3</sub>(bipy)] (<b>2</b>) and [Re{N(<i>p</i>Tol)C(O)CHPh<sub>2</sub>}(CO)<sub>3</sub>(bipy)] (<b>3</b>), respectively. The reaction of <b>1</b> with activated acetylenes containing at least one alkoxycarbonyl group afforded the compounds [Re{N(<i>p</i>Tol)C(R‘)C(R)C(OH)}(CO)<sub>3</sub>(bipy)] (<b>4a</b>−<b>c</b>). The formation of the metallacycle present in these compounds involves the activation of one of the carbonyl ligands of <b>1</b>. The structures of the complexes <b>2</b>, <b>3</b>, and <b>4b</b> have been determined by single-crystal X-ray diffraction. <sup>13</sup>C NMR and crystallographic data indicate that the metal-bonded carbon atom of the metallacycle possesses carbene character.