Cyclization Reactions of Ruthenium Vinylidene Complexes

Abstract

Treatment of [Ru]-CdC(Ph)C(dNPh)S (2, [Ru] ) (η 5 -C 5 H 5 )(dppe)Ru, dppe ) Ph 2 PCH 2 -CH 2 PPh 2 ) with ICH 2 CN at room temperature affords the S-alkylation product [Ru]dCd C(Ph)C(dNPh)SCH 2 R + (3a, R ) CN). Deprotonation of 3a by n-Bu 4 NOH in acetone induces a novel cyclization reaction and yields the neutral five-membered-ring heterocyclic complex[Ru]-CdC(Ph)C(dNPh)SCHCN (5a), which isomerizes to the 2-aminothiophene complex[Ru]-CdC(CN)SC(NHPh)dC(Ph) (6a). Treatment of 2 with organic bromides BrCH 2 R affords both S-alkylation products (3b, R )Ph) in varying ratios. Base-induced cyclization of a mixture of 3b and 4b occurs only for the 3b component to afford [Ru]-CdC(Ph)C(dNPh)SCHCO 2 CH 3 (5b), whereas cyclization of a mixture of 3c and 4c occurs for both complexes, yielding 5c and the pyrrole-2-thione complex[Ru]-CdC(Ph)C(dS)N(Ph)CH(p-C 6 H 4 CN) (7c), respectively. Cyclization of a 3d-4d mixture occurs only for 4d to afford [Ru]-CdC(Ph)C(dS)NPhCHPh (7d). The structures of 6a and 7c were determined by single-crystal X-ray diffraction analysis.

Coordination-induced bond weakening and small molecule activation by low-valent titanium complexes

“…The coordination of silanes to a metal center by η 2 σ bonds has been reported to induce bond weakening of the Si-H bond. [51][52][53][54] This nonclassical interaction has been studied in both early-and mid-transition metal complexes. 53,54 These complexes exhibit special structural and bonding characteristics attributed to the weak σ Si-H bond and the hypervalency of Si.…”

Novel Thiotetraazapentalene Complexes from the Reaction of a Ruthenium Azide Complex with Alkyl Isothiocyanates

“…We reported previously the reactions of ruthenium acetylide complexes with isothiocyanate, which yielded ligands containing four-and six-membered heterocyclic rings. [10,11] Because the reaction of arylsulfonyl isothiocyanates with alkyl azides is known [12] to give 4-alkyl-5-arylsulfonylimino-1,2,3,4-thiatriazolines we were interested in studying the reactions of ruthenium azide complexes with isothiocyanates. Surprisingly, these reactions give ruthenium thiotetraazapentalene [13,14] complexes containing a hypervalent sulfur atom.…”

Reaction of ruthenium complexes containing heterocyclic thiazine–thione ligand

“…Recently we reported that the reaction of isocyanates and isothiocyanates with two ruthenium acetylide complexes resulted in sequential additions of the organic substrate to the acetylide ligand to produce novel heterocyclic ligands [ Subsequent cyclization reactions of these vinylidene complexes induced by deprotonation generates neutral heterocyclopentenyl complexes [2]. We also reported that the reaction of the ruthenium dihydrofuranyl complex (C 5 Me 5 )(dppp)Ru Ã/ / ae /C Ä/C(Ph)CH(CN)C(CH 3 ) 2 O/ / with electrophiles, such as XCH 2 R, H ' and HgCl 2 , afforded a series of cationic carbene complexes [3].…”