Formation of Organometaliic Heterocycles by S-alkylated and N-alkylated Ruthenium Vinylidene Complexes

摘要

Treatment of [RujOCPh (1, [Ru] = (n~5-C_5H_5)(dppe)Ru, dppe - Ph2PCH_2CH_2PPh_2) with PhN=C=S at room temperature affords the [2 + 2] cycloaddition product [Ru]-C=C(Ph)C(=NPh)S (2) which contains a four-membered-ring heterocycle. A series of cationic S-alkylated ruthenium vinylidene complexes [Ru]=C=C(Ph)C(=NPh)SCH_2R~+ (3a, R = CONH_2; 3b, R = CH=CH_2; 3c, R = p-C_6H_4CF3) and N-alkylated ruthenium vinylidene complexes [Ru]=OC(Ph)C(=S)N(Ph)CH_2R~+ (4b, R = CH=CH2; 4c, R =p-C_6H_4CF.O are prepared from 2 with organic halides at room temperature with high yields, Deprotonation of 3a and 3c by n-Bu_4NOH in acetone induces novel cyclization reactions via C-C bond formation and yields neutral five-membered-ring heterocyclic complexes [Ru]-C=C(Ph)C(=NPh)SCHR (5a, R - CONH_2; 5c, R =p-C_6H_4CF_3). In a similar manner, deprotonation of 4b and 4c by NaOMe in CH_2C1_2 also induces another cyclization to yield the pyrrole-2-thione complexes [Ru]-C=C(Ph)C(=S)N(Ph)CHR (6b, R = CH-CH_2; 6c, R = p-C6H4CF3). At room temperature, 5c isomerizes to the 2-aminothiophene complex [Ru]-C=C(p-C_6H_4CF_3) SC(NHPh)=C(Ph) (7c) in solution.