Formation of organometallic heterocycles by S-alkylated and N-alkylated ruthenium vinylidene complexes

摘要

Treatment of [Ru]C=-CPh (1, [Ru] = (eta(5)-C5H5)(dppe)Ru, dppe = Ph2PCH2CH2PPh2) 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)SCH2R+ (3a, R = CONH2; 3b, R = CH=CH2; 3c, R =p-C6H4CF3) and N-alkylated ruthenium vinylidene complexes [Ru]=C=C(Ph)C(=S)N(Ph)CH2R+ (4b, R = CH=CH2; 4c, R =P-C6H4CF3) are prepared from 2 with organic halides at room temperature with high yields. Deprotonation of 3a and 3c by n-Bu4NOH 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 = CONH2; 5c, R =P-C6H4CF3)In a similar manner, deprotonation of 4b and 4c by NaOMe in CH2Cl2 also induces another cyclization to yield the pyrrole-2-thione complexes [Ru]-C=C(Ph)C(=S)N(Ph)CHR (6b, R = CH=CH2; 6c, R = P-C6H4CF3). At room temperature, 5c isomerizes to the 2-aminothiophene complex [Ru]- =C(p-C6H4CF3) SC(NHPh)= (Ph) (7c) in solution. [References: 28]