Reaction of 1-naphthylamine with ethyl benzoylacetate gives the corresponding benzoyl acetamide derivative 1, which undergoes cyclization to 4-phenylbenzo[h]quinolin-2(1H)-one (2) in the presence of H2SO4. Bromination with POBr3, followed by reaction with n-BuLi and DMF, gives 4-phenylbenzo[h]quinoline-2-carbaldehyde (4), which is converted to the corresponding oxime hydrochloride 5 with NH2OH·HCl. Hydrogenation of 5 catalyzed by 10% Pd/C (type 338) leads to 4-phenyl-2-aminomethylbenzo[h]quinoline hydrochloride (HCNNPh·HCl, 6) isolated in high yield. Similarly, the 4-methyl-2-aminomethylbenzo[h]quinoline derivative (HCNNMe·HCl, 12) is prepared starting from 1-naphthylamine and 2,2,6-trimethyl-4H-1,3-dioxin-4-one, following the route for 6. Reaction of RuCl2(PPh3)3 with a diphosphine (PP), the HCl salt 6, and NEt3 in 2-propanol leads to the pincer complexes RuCl(CNNPh)(PP) (PP = Ph2P(CH2)3PPh2, 13; Ph2P(CH2)4PPh2, 14; 1,1′-bis(diphenylphosphino)ferrocene, 15). The methyl derivatives RuCl(CNNMe)(PP) (PP = Ph2P(CH2)3PPh2, 16; Ph2P(CH2)4PPh2, 17; 1,1′-bis(diphenylphosphino)ferrocene, 18) are obtained in a similar way using 12 in place of 6. Treatment of [RuCl2(p-cymene)]2 with rac-BINAP, 6, and NEt3 affords RuCl(CNNPh)(BINAP) (19), isolated as a mixture of two diastereoisomers (3:4 molar ratio). The chiral RuCl(CNNPh)[(S,R)-JOSIPHOS] (20) is obtained as a single isomer from [RuCl2(p-cymene)]2, (S,R)-JOSIPHOS, and 6. Complexes 13-20 efficiently catalyze the transfer hydrogenation of acetophenone in 2-propanol at reflux in the presence of NaOiPr (2 mol%) with S/C = 5000-20-000 and at high rate (TOF up to 6.7 × 103 min-1). With complexes 13, 15, 17, and 18 several ketones of commercial-grade purity have been reduced to alcohols, including the bulky RCO(tBu) (R = Me, Ph) substrates. With 20 acetophenone is reduced to (S)-1-phenylethanol with 85% ee. The pincer complexes 13-15 and 18 are also found highly active in the hydrogenation of ketones at 40 °C with an S/C = 10-000, under 5 bar of dihydrogen in methanol and in the presence of 2 mol % of a base (NaOH, KOH, NaOMe)

The dicarbonyl complex RuCl 2 (L) 2 (CO) 2 (1) was easily prepared by reaction of ruthenium chloride hydrate with formic acid and L (L = (2,6-Me 2 C 6 H 3 )PPh 2 ) in ethanol at reflux, via the [RuCl 2 (CO) 2 ] n intermediate. Alternatively, 1 was obtained from [RuCl 2 (CO) 3 ] 2 and L by CO elimination. Reaction of 1 with NEt 3 in toluene at reflux afforded the cyclometalated derivative RuCl{(2-CH 2 -6-MeC 6 H 3 )PPh 2 }-(L)(CO) 2 (2). A simple one-pot synthesis of 2 was achieved by treatment of RuCl 3 hydrate with formic acid, L, and NEt 3 . The cyclometalated dicarbonyl complexes [Ru{(2-CH 2 -6-MeC 6 H 3 )PPh 2 }(NN)(CO) 2 ]Cl (NN = ethylenediamine, 3; 2-(aminomethyl)pyridine, 4; (R,R)-1,2-diphenylethane-1,2diamine, 5) were isolated by reaction of 2 with the corresponding dinitrogen ligand in methanol at reflux. Complexes 1−4 catalyze the transfer hydrogenation (TH) of acetophenone in 2-propanol at reflux (S/C = 1000 and TOF up to 30 000 h −1 )with alkali base (1−5 mol %), whereas 5 leads to (S)-1-phenylethanol with 68% ee. The derivatives 1−5 catalyze the hydrogenation (HY) of several ketones (H 2 , 30 bar) at 70 °C in MeOH and EtOH with KOtBu (2 mol %) (S/C and TOF up to 25 000 and 14 000 h −1 ). Addition of NN ligands to 1 and 2 in situ increases both the TH and HY activity, with ampy displaying the better performance. Heating of the cationic complex 3 in solid state and in solution leads to decarbonylation, affording the neutral monocarbonyl compound RuCl{(2-CH 2 -6-MeC 6 H 3 )PPh 2 }(en)(CO) (6) which was found active in the ketone HY.

The alkoxycarbonylation of a-chloro ketones with carbon monoxide in alcoholic solvents could be optimized to generate b-keto esters in high yields using much lower catalyst loadings than previously reported in the literature. Among the different screened parameters, the nature of the ligand proved to be the most crucial one, the Xantphos ligand affording the highest yields. The scope of the reaction could then be extended to a wide variety of chloro ketones with different types of alcohols.