Orientation towards asymmetric transfer hydrogenation of ketones catalyzed by (pyrazolyl)ethyl)pyridine Fe(II) and Ni(II) complexes

Reduced graphene oxide/iron oxide hybrid composite material as an efficient magnetically separable heterogeneous catalyst for transfer hydrogenation of ketones

“…10 mg of rGO/Fe 3 O 4 composite as catalyst, 5 ml of i ‐PrOH as hydrogen donor and 5 ml of Na‐ i ‐OPr as the base at 80 C for 3 hours) in hand, we studied the scope and efficiency of this methodology and hence employed various substrates to investigate the scope of the catalyst (Table ). It was observed that hydrogenation of benzophenone (Table , entry 1) is slower than that of acetophenone (Table , entry 3) which may be attributed to increased ring strain due to two bulky phenyl rings in the benzophenone substrate . 4‐Bromo benzophenone (Table , entry 2) gives a better result than benzophenone which may be due to the electron‐withdrawing effect of Br at p ‐position.…”

Structural and theoretical studies of the methoxycarbonylation of higher olefins catalysed by (Pyrazolyl‐ethyl)pyridine palladium (II) complexes

“…Ligands 2‐[1‐(3,5‐dimethylpyrazol‐1‐yl)ethyl]pyridine ( L1 ) and 2‐[1‐(3,5‐diphenylpyrazol‐1‐yl)ethyl]pyridine ( L2 ) were prepared following our recently published procedures . Reactions of synthons 2‐[1‐(3,5‐dimethylpyrazol‐1‐yl)ethyl]pyridine (L1) and 2‐[1‐(3,5‐diphenylpyrazol‐1‐yl)ethyl]pyridine (L2) with the [Pd (COD)Cl 2 ] or [Pd (COD)ClMe] metal salts produced the corresponding neutral complexes 1–4 as brown solids in low to good yields (44%–84%) as shown in Scheme .…”

“…The motivation for the incorporation of a methyl group in the methylene bridge was to introduce chirality at the methylene carbon for possible application in asymmetric methoxycarbonylation catalysis. However, as we previously discussed, only racemic mixtures of the ligand were obtained. In this current work, we therefore report the syntheses of palladium (II) complexes of these ligands, their structural characterization and applications as catalysts in methoxycarbonylation of higher olefins.…”

Electrophile‐Directed Diastereoselective Oxonitrile Alkylations

“…[16] Diastereoselective alkylationsw ith as eries of oxonitriles and secondary electrophiles are stereoselective ande fficient (Table 1). In contrast, alkylations of 6a with the isopropyl-substituted bromide 7e andt he pyridyl electrophile 7f [17] were minimally selective ( Table 1, entries 5a nd 6). In contrast, alkylations of 6a with the isopropyl-substituted bromide 7e andt he pyridyl electrophile 7f [17] were minimally selective ( Table 1, entries 5a nd 6).…”

“…Varying the ortho-substituent from methyl (7b)t o methoxy (7c)o rb romine (7d)h ad little impacto nt he diastereoselectivity ( Table 1, verse chelation with am ethoxy substituent. In contrast, alkylations of 6a with the isopropyl-substituted bromide 7e andt he pyridyl electrophile 7f [17] were minimally selective ( Table 1, entries 5a nd 6). Alkylations of the naphthyl oxonitrile 6b ( Table 1, entries7 and 8), electron-deficient( Ta ble 1, entries 9 and 10) and electron-rich oxonitriles( Ta ble 1, entries 11 and 12) installed the contiguouss tereocentersw ith good diastereoselectivity.A lkylations with 2-thienyl and 3-thienyl oxonitriles 6f and 6g afforded diastereomeric ratios in excess of 6.5:1 (Table1,e ntries 13-15) whereas alkylation with the sterically less demanding furan 6f afforded a2 .5:1 ratio of diastereomers ( Table 1, entry 16).…”