Insertion reactions of CO into the rhenium-nitrogen bond. eta(2)-carbamoyl complexes and their reactions

摘要

Deprotonation of [(CO)(2)RReNH(CH3)CH2CH2(eta(5)-C5H4)]X-+(-) (R = CO2Me, CO2Et; X = Br) followed by heating under a CO atmosphere yields the corresponding CO insertion compound (CO)(2)RReC(=O)N(CH3)CH2CH2(eta(5)-C5H4). An anologous insertion reaction proceeds more rapidly for the complexes [(CO)(2)XReNH(CH3)CH2CH2(eta(5) -C5H4)]Y-+(-) (X = Br, I, PhS, and PhSe) in which X is a strong electron-withdrawing group. Without the presence of external ligands, the oxygen of the resultant carbamoyl group binds to the rhenium to fulfill the 18-electron rule. The eta(2)-carbamoyl selenolate complex [(CO)PhSeRe(eta(2)-C=O)N(CH3)CH2CH2(eta(5)-C5H4)] (9b) has been characterized by X-ray crystallography. Upon addition of two-electron-donor ligands, such as CO, isocyanides, and trialkyl phosphites, the eta(2)-carbamoyl complexes convert cleanly to the corresponding eta(1)-carbamoyl complexes. [References: 22]