Ruthenium Metathesis Catalysts Containing Chelating Aryloxide Ligands

Abstract

Olefin metathesis catalysts containing chelating aryloxide donors, RuXX‘(IMes)(py)(CHPh) (5, XX‘ = 3,5-dichloro-2-oxidobenzenesulfonate; 6, XX‘ = catecholate), are accessible in high yield by reaction of o-sulfonato aryloxide or catecholate salts, respectively, with RuCl2(IMes)(py)2(CHPh). Isomerization to π-bound aryloxides, as found with phenoxide ion or 2‘-(diphenylphosphino)-1,1‘-binaphthyl-2-olate, is suppressed by use of these smaller, more rigid, chelate rings. Preliminary investigations indicate that the catecholato derivative exhibits metathesis activity approaching that of the recently reported, highly active catalyst RuCl(OC6Br5)(IMes)(py)(CHPh).

Ruthenium–Amido Complexes: Synthesis, Structure, and Catalytic Activity in Olefin Metathesis

“…The search for new improved catalysts for ruthenium metathesis focused mainly on the modifications of alkylidene ligand or the L 2 units in [L 2 X 2 Ru=CHR] scaffold characteristic of the family of Grubbs catalyst has made considerable progress and led to development of new generations of catalysts 1a. 2 Increasing number of reports is also observed on exchange of anionic ligands, in particular parent chloride ligands with other halides,3a,b alkoxides,3c aryloxides,3d–g carboxylates including perfluorocarboxylates,3h–o diketonates,3p isocyanates (OCN − ),3l,q isothiocyanates (SCN − ),3l,q sulphonates,3e,j,r,s phosphonates,3r and nitrate 3l,t. Several accounts report application of chelating carboxylates,4a–e alkoxides and aryloxides3t, 4f–g including Schiff bases 4h,i.…”

‘Pseudo-halide’ Derivatives of Grubbs- and Schrock-Type Catalysts for Olefin Metathesis

“…Mol and co-workers accomplished the replacement of chloride ligands on Ru-based catalysts with carboxylates to make Ru-alkylidene carboxylate dimers. 3, 14 Fogg and co-workers [15][16][17][18][19] and our group 5,20-34 followed with Research Conference (GRC). In 2010, she completed her PhD in polymer chemistry at Virginia Tech in Blacksburg, VA.…”

Integrating the Schrock and Grubbs Catalysts: Ruthenium–Binaphtholate Catalysts for Olefin Metathesis

“…Thus, reaction of 4 with phenoxide affords the piano-stool product [RuX(h 5 -C 6 H 5 O)(PPh 3 ) 2 ], [18] but s-OAr products are accessible on use of electron-deficient aryloxides, [20] or aryloxides incorporated into a rigid (e.g., five-membered) chelate ring. [21] This behavior proved an accurate predictor for the accessibility of [Ru]=CHR complexes containing electrondeficient perhaloaryloxides [19] and catecholates; [22,23] sixmembered chelates are also accessible. [23][24][25] With more flexible, seven-membered chelate rings, p coordination of one aryl ring is expected, based on the reaction of 4 a with the heterobifunctional phosphine-phenoxide proligand M(binop) (binop = 2-diphenylphosphanyl-1,1'-binapthyl-2'-olate; Scheme 2, top).…”