Cycloaddition and Related Reactions of Ruthenium Acetylide Complexes with EtO2CNCS

Abstract

Treatment of ruthenium acetylide complexes Cp(L)(L')RuC=CPh (la, LL' =dppe, dppe = Ph2PCH2CH2PPh2; lb, L = PPh3, L' = P(Ome)3 with 1.1 equivalent of EtO2CN=C=S at room temperature for one hour results in the [2 + 2] cyc1oaddition to yield the four-membered-ring products Cp(L)(L')Ru-C=C(Ph)C(=NCO2Et)S (2a, LL'=dppe.dppe=Ph2PCH2CH2PPH2;2b,L=PPh3,L'=P(OMe)3).The reaction of complexes 2a and 2b react with 5 fold excess of EtO2CNCS affords the heterocyclic six-membered-ring complexes Cp(L)(L')Ru-C=C(Ph)C(=S)N(CO2Et)C(NCO2Et)S(3a, LL' = dppe, dppe = Ph2PCH2CH2PPh2; 3b, L = PPh3, L' = P(OMe)3). Complex 3a decomposes in excess EtO2CNCS in CH2Cl2 solution to yield a new six-membered-ring complex Cp(dppe)Ru-C=C(Ph)C(SCH2SH)N(=O)O (4). Two molecules of complex 4 in solutions can dimerize into a binuclear complex [Cp(dppe)Ru-C=C(Ph)C(S-)N(=O)O]2CH2 (5).