Syntheses of RuHCl(CO)(PAr₃)₃ and RuH₂(CO)(PAr₃)₃ Containing Various Triarylphosphines and Their Use for Arylation of Sterically Congested Aromatic C–H Bonds

Abstract

A series of ruthenium complexes, RuHCl(CO)(PAr 3 ) 3 and RuH 2 (CO)(PAr 3 ) 3 , containing various triarylphosphines were synthesized. Screening of these complexes as catalysts for direct arylation of sterically congested ortho C−H bonds of aromatic ketones improved the yields of the arylation products.

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

“…Kakiuchi and co-workers tackled the problem of arylating sterically demanding diaryl and aryl–alkyl ketones by designing Ru catalysts of the general structures [RuHCl(CO)(PAr 3 ) 3 ] and [RuH 2 (CO)(PAr 3 ) 3 ]. 76 3,3′,5,5′-Tetramethylbenzophenone served as model substrate and a boronic acid ester as the aryl source. For this substrate, [RuHCl(CO)(P(4-MeO-3,5-Me 2 C 6 H 2 ) 3 ) 3 ] turned out to be the best performing catalyst, whereas for the pivalophenone derivative 1-(3,5-dimethylphenyl)-2,2-dimethylpropan-1-one [RuH 2 (CO)(P(3-MeC 6 H 4 ) 3 ) 3 ] performed best ( Scheme 1A ).…”

In Situ Generation of Ruthenium Carbonyl Phosphine Complexes as a Versatile Method for the Development of Enantioselective C−O Bond Arylation

“…Other triarylphosphines were also examined using the same protocol (entries 3–6). While the arylation did not proceed by using P(2‐MeC 6 H 4 ) 3 , the [RuHCl(CO)(PAr 3 ) n ]‐ or [RuH 2 (CO)(PAr 3 ) n ]‐type complex of which has been neither reported nor prepared in our group (entry 3), the reaction in the presence of P(3‐MeC 6 H 4 ) 3 or P(4‐MeC 6 H 4 ) 3 afforded 4 as a major product (entries 4 and 5). The arylation also proceeded using P(4‐F 3 CC 6 H 4 ) 3 as a ligand to give 3 and 4 in 17 and 61 % yields, respectively, with excellent material balance (entry 6).…”

“…The arylation also proceeded using P(4‐F 3 CC 6 H 4 ) 3 as a ligand to give 3 and 4 in 17 and 61 % yields, respectively, with excellent material balance (entry 6). It is important to note that the [RuHCl(CO)(PAr 3 ) 3 ]‐ and [RuH 2 (CO)(PAr 3 ) 3 ]‐type complexes could not be prepared from P(4‐F 3 CC 6 H 4 ) 3 by our previously reported method and its applicability as a ligand has not been evaluated for the C−O arylation . In contrast, the reactions using trialkylphosphines, such as PCy 3 , P t Bu 2 Me, and P i Pr 3 provided monoarylation product 3 as a major product (entries 7–9), as observed for our previously reported C−O arylation of 1 by using [RuHX(CO)(PR 3 ) 2 ]‐type complexes (X=Cl, OAc) as catalysts .…”

Two tris(3,5-disubstituted phenyl)phosphines and their isostructural PV oxides

“…The two bulky triarylphosphines (I) and (III) are of considerable interest in coordination chemistry and catalysis (Kakizoe et al, 2017;Lian et al, 2017;Ogiwara et al, 2017;Nishikawa et al, 2016;Naruto et al, 2015;Jover et al, 2010;Romain et al, 2000) and have been investigated for frustrated Lewis-pair activity (Wang & Stephan, 2014;Ullrich et al, 2010). The synthesis of (I) was first mentioned in the nonpatent literature by Hengartner et al (1979) and in more detail twelve years later (Culcasi et al, 1991) and is now commercially available from several sources, but its crystal structure has not been reported.…”