Highly efficient polymer-based nanoreactors for selective oxidation of alcohols in water

Microwave-assisted oxidation reaction of primary alcohols with sensitive functional groups to aldehydes using ruthenium diphosphorus complexes

“…For example, bulky t-butyl groups were employed to induce a steric hinderance effect at the phosphorus donors, whereas a strong electron-donating p-tolyl group was used to induce an electronic (inductive) effect. The structures of the synthesised ligands were determined by 1 H NMR, 13 C NMR, 31 P NMR and HR-MS and in some cases further confirmed by X-ray crystallography where the crystal of the targeted compound was successfully grown (L13). 8 The various xanthene type ligands L3-L14 were then tested in the oxidation reaction under the optimised reaction conditions (Table 2).…”

“…The organic layers were extracted with DCM (3 x 20 mL). After drying over anhydrous MgSO4, filtration and evaporation, the residue was purified by column chromatography on silica gel (hexane, 100%, Rf = 0.6) to give a solid: yield: 2.2 g (81%); 1 H NMR (CDCl3, 400 MHz) δ/ppm: 7.38 (dd, J 7.6, 1.3 Hz, 2H), 7.17 (m, 4H), δ 7.09 (td, J 7.6, 1.5 Hz, 2H), 2.09 (s, 6H; =C(CH3)2); 13…”

“…The crude product was washed with hexane (3 x 10 mL), dissolved in DCM, and an equal volume of EtOH added slowly. The solution was left to recrystalise at room temperature to give yellow crystals: yield 1.1 g (56%); 1 H NMR (CDCl3, 400 MHz,) δ/ppm: 7.59 -6.96 (m, 20 H P(C6H5)2 and 2H xanthene ring), 6.32 (bs, 2H), 2.38 (t, J 7.5 Hz, 4H), 1.62 (s, 6H), 1.48 -0.98 (m, 16H), 0.84 (t, J 6.9 Hz, 6H); 13 C NMR (CDCl3, 101 MHz) δ/ppm: 150.9 (t, J (P,C) = 19.6 Hz, CO), 137.7 (dd, J (P,C) = 7.2, 5.9 Hz, phenyl C-ipso, PC), 137.1 (C), 133.9 (t, J (P,C) = 10.4 Hz, CH phenyl), 131.9 (CH), 129.…”

“…Compound L13 was prepared analogously to L11 using L2 (0.7 g, 3.2 mmol), TMEDA (1.2 mL, 7.9 mmol), nBuLi (5.0 mL, 7.9 mmol) and P(p-tolyl)2Cl (1.8 mL, 7.9 mmol) in dry hexane (5 mL) Yield 1.0 g (50%); 1 H NMR (CDCl3, 400 MHz) δ/ppm: 7.38 (dd, J 7.6, 1.3 Hz, 2H), 7.17 (m, 4H), 7.09 (dquar, J 7.6, 1.7, J(P,H) = 1.6 Hz 2H), 2.35 (s, 12H, CH3-C6H4P). 2.09 (s, 6H,CCH3); 13…”

“…The oxidation reaction is one the most fundamental reactions in synthetic organic chemistry and has been the subject of numerous studies. [10][11][12][13][14][15][16][17] Ruthenium is a well stablished metal for the oxidation of alcohols. 11,18 Aldehydes, as a result of their increased electrophilic nature, are more reactive and suitable for a broader range of transformations than the precursor alcohols.…”