| 99% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; dihydrogen peroxide; benzenesulfonic acid; potassium bromide In dichloromethane; lithium hydroxide monohydrate at 20℃; for 24h; |
|
| 99% |
With dihydrogen peroxide In lithium hydroxide monohydrate at 100℃; for 5.5h; chemoselective reaction; |
|
| 99% |
With dihydrogen peroxide In lithium hydroxide monohydrate; ethyl acetate at 50 - 55℃; for 0.833333h; |
|
| 99% |
With titanium(IV) dioxide; oxygen at 29.84℃; for 6h; Sealed tube; Irradiation; |
|
| 99% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; oxygen; anhydrous sodium carbonate In acetonitrile at 75℃; for 6h; |
|
| 99% |
With 1,1,1,3',3',3'-hexafluoro-propanol; oxygen; HNO3 at 20℃; for 23h; |
|
| 99% |
With 1-methyl-1H-imidazole; copper (I) iodide; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical In acetonitrile at 20℃; for 1h; |
|
| 99% |
With N-chloro-N-(phenylsulfonyl)benzenesulfonamide In acetonitrile at 20 - 25℃; for 0.0833333h; Inert atmosphere; chemoselective reaction; |
General procedure for oxidation of electron-deficient alcohol and ether
General procedure: In a 3 neck, 50.0 mL round-bottomed flask arranged with a nitrogen atmosphere, calcium chloride guard tube, and magnetic stirrer was charged with acetonitrile 5.0 mL followed by alcohol or ether (3.6 mmol). The reaction mixture was cooled to 20-25 °C and added NCBSI reagent (3.6 mmol) at once under a stream of nitrogen. After addition, the colour of the reaction changes to pale yellow and then colourless. The reaction was monitored by TLC and confirm with 2,4-DNPH spray. On completion of the reaction, the solvent was evaporated under reduced pressure. The residue was extracted in 5.0 mL DCM and washed with 1% sodium bicarbonate solution 5.0 mL, phase-separated, dried over anhyd. Na2SO4 and evaporated under reduced pressure to give the product as stated. The purity of the product was determined by G.C. |
| 98% |
With dihydrogen peroxide In lithium hydroxide monohydrate; ethyl acetate at 45℃; |
2.6 Typical procedure for oxidation of alcohols
General procedure: All the reactions were carefully carried out at 40°C in a 25ml flask. In a typical procedure an amount of catalyst along with H2O2 was used for the oxidation process under mild conditions. The oxidation process was monitored by thin layer chromatography technique. |
| 98% |
With 4-dimethylaminopyridine; C25H30F17N5O4S(1-)*K(1+); oxygen; copper(II) sulphate In lithium hydroxide monohydrate at 25℃; for 1h; chemoselective reaction; |
|
| 98% |
With tert.-butylhydroperoxide In toluene at 120℃; for 4h; |
|
| 98% |
With dihydrogen peroxide In lithium hydroxide monohydrate at 50℃; for 2.5h; Green chemistry; |
|
| 98% |
With potassium carbonate In n-heptane at 80℃; for 24h; |
S4. Procedure for the synthesis of aldehydes and ketones
General procedure: A magnetic stir bar, 0.5 mmol alcohol and 3 mL n-heptane solvent were added to 20 mL glass tube. Then, 35mg catalyst and 10 mol% of K2CO3 were added. The glass tube containing reaction mixture was f itted withseptum and connected to a balloon containing one bar of air. Then the glass tube was placed into a preheatedaluminum block at 85°C. Temperature inside the reaction tube was measured to be 80 oC and this temperaturehas been taken as the reaction temperature. The reaction was allowed to progress under continuous stirringfor the required time at 80 °C. Af ter completion of the reaction, the glass tube was cooled down to roomtemperature. Afterwards, the catalyst was f iltered-off and washed with ethyl acetate. The solvent f rom thef iltrate containing the reaction products was removed in vacuum and the corresponding aldehyde/ketone waspurif ied by column chromatography. All products were analyzed by GC-MS and NMR spectroscopy analysis.In the case of yields determined the by GC, 100 μL n-hexadecane was added to the reaction vial containingthe products and diluted with ethyl acetate. Then, the reaction mixture containing catalyst and products wasf iltered through a plug of silica and the filtrate containing product was analyzed by GC. |
| 97% |
With dihydrogen peroxide In lithium hydroxide monohydrate; acetonitrile at 65℃; for 1.66667h; Green chemistry; chemoselective reaction; |
|
| 97% |
With dihydrogen peroxide at 25℃; for 0.0833333h; Sonication; |
|
| 97% |
With cerium(III) bromide; dihydrogen peroxide In 1,4-dioxane; lithium hydroxide monohydrate at 20℃; |
|
| 96% |
With 4-methyl-morpholine; chromium(VI) oxide; hydrogenchloride In diethyl ether; chloroform at 65℃; for 0.0833333h; microwave irradiation; |
|
| 96% |
With hydrogen bromide; oxygen; NaNO2 In lithium hydroxide monohydrate; acetonitrile at 80℃; for 6h; |
|
| 96% |
With hydrogenchloride; platinum; sodium chloride In chloroform; lithium hydroxide monohydrate at 30℃; Electrolysis; |
|
| 95% |
With Amberlyst A-27 supported permanganate In dichloromethane |
|
| 95% |
With hydrogenchloride; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; NaNO2 In dichloromethane; lithium hydroxide monohydrate at 20℃; for 10h; in air; |
|
| 95% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; hydroxylamine; oxygen In lithium hydroxide monohydrate; 1,2-dichloro-ethane at 80℃; for 4h; Autoclave; |
|
| 95% |
With Fe2(SO4)3; TEMPOL; oxygen; NaNO2 In lithium hydroxide monohydrate; acetonitrile at 20℃; for 12h; |
The oxidation of alcohols was carried out under O2 in a 50-mL two-necked, round-bottom flask equipped with a magnetic stirrer. Typically, Fe2(SO4)3 (0.25 mmol) and TMHPO (0.25 mmol) were added to the flask, followed by 15 mL of a CH3CN/H2O (1:2) solvent mixture. After stirring for 5 min, the alcohol (5 mmol) was added, followed by NaNO2 (0.25 mmol). The resulting mixture was stirred at room temperature and 1 atm pressure of oxygen. When the reactions were completed, the reaction mixture was transferred to a separating funnel and extracted with dichloromethane. The organic layer was dried over anhydrous Na2SO4 and concentrated and further purified by flash chromatography to give the desired product. |
| 95% |
With sulfuric acid; dihydrogen peroxide; sodium bromide In 1,4-dioxane; lithium hydroxide monohydrate at 70℃; Flow reactor; Green chemistry; |
|
| 95% |
With (1,3-bis(2,6-di-iso-propylphenyl)-4,5-dihydroimidazol-2-ylidene) copper chloride; oxygen; potassium hydroxide In dichloromethane at 20℃; for 12h; Molecular sieve; |
|
| 95% |
With tert.-butylhydroperoxide at 80℃; for 4.33333h; Green chemistry; |
General procedure for the oxidation of alcohols tocarbonyl compounds
General procedure: The alcohol (1 mmol) was added to a mixture of TBHP(1 mmol) and VO(ephedrine)2MNPs (50 mg) in PEG(1 mL), and then the mixture was refluxed at 80 C for thetime specified. The progress was monitored by TLC (EtOAc/n-hexane, 1/2). After completion of the reaction, the catalystwas separated from the product by an external magnet(within 5 s), and the mixture was washed with EtOAc(25 mL) and decanted. The decanted mixturewas washedwith 30% NaOH (5 mL) and the organic layer was dried overanhydrous Na2SO4. The evaporation of EtOAc underreduced pressure gave the pure products in 85e98% yields. |
| 94% |
With iron nitrate (III) at 60℃; for 0.5h; |
|
| 94% |
With oxygen; potassium carbonate In toluene at 100℃; for 9h; |
|
| 94% |
With C30H24AgBr4N8(1+)*AgBr2(1-); N,N,N-trimethylbenzenemethanaminium hydroxide In toluene at 20℃; for 12h; Molecular sieve; Schlenk technique; |
|
| 94% |
With hexaammonium heptamolybdate tetrahydrate; dihydrogen peroxide In lithium hydroxide monohydrate; Methylcyclohexane at 50℃; for 4h; Ionic liquid; Green chemistry; |
|
| 94% |
With dihydrogen peroxide at 50℃; |
4 3. Typical procedure for alcohol oxidation
General procedure: The oxidation process was carried out under identical condi-tions with special care. The oxidation of alcohols was carried outwith H2O2in the presence of different synthesized catalysts atatmospheric pressure and temperature of 50C. |
| 94% |
With oxygen; Azobenzene; sodium bromide In 1,4-dioxane at 80℃; for 36h; |
|
| 94% |
With cobalt(II)-meso-tetra(4-carboxyphenyl)porphyrin on TiO2/WO3 nanohybrid In acetonitrile at 30℃; for 1h; UV-irradiation; |
|
| 94% |
With lactate; dihydrogen peroxide at 30℃; for 7h; |
Typical procedure for the oxidation of alcohols
General procedure: A mixture of alcohol (1 mmol) and lactic acid (1 mL) was charged in 25 mL round bottom flask subjected to constant magnetic stirring at room temperature (30°C). The reaction mixture was further activated by addition of 30% H2O2 (1.07 equiv.). The reaction progress was monitored by GC. After completion of the reaction, Dichloromethane (2×6 mL) was added to the reaction mixture and then washed with distilled water (2×2mL). The organic layer was separated and dried over Na2SO4 and removed under reduced pressure. The crude product was obtained by evaporation method and again purified by column chromatography using ethyl acetate and n-hexane as eluting system. |
| 93% |
With ammonium bromide In lithium hydroxide monohydrate; acetonitrile at 60℃; for 3h; |
|
| 93% |
With oxygen In lithium hydroxide monohydrate at 80℃; for 7.5h; Green chemistry; |
|
| 93% |
With ammonium hydroxide; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; oxygen In ethanol at 50℃; for 24h; |
10 4.5. General procedure for the aerobic alcohol oxidation
General procedure: Under an air atmosphere, a Schlenk tube was charged with MCM-41-bpy-CuI (40 mg, 0.025 mmol), alcohol (0.5 mmol), TEMPO (4 mg, 0.025 mmol), aqueous ammonia (0.5 mmol, 25e28%, w/w) and EtOH (1.0 mL). The mixture was stirred at 50 °C for 18-48 h. After completion of the reaction, the reaction mixture was cooled to room temperature, diluted with ethyl acetate (10 mL), and filtered. The MCM-41-bpy-CuI complex was washed with EtOH (2*5 mL), and Et2O (5 mL) and reused in the next run. The filtrate was concentrated under reduced pressure and the residue was purified by flash column chromatography on silica gel (petroleum/ethyl acetate=15:1 to 10:1) to provide the desired product. |
| 93% |
With [Cu(6-(2-carboxylatophenylcarbamoyl)picolinate)](4-dimethylaminopyridine)*3H2O; dihydrogen peroxide In acetonitrile at 45℃; |
Typical procedure for the study of catalytic properties
General procedure: To investigate the catalytic activity of complex (3), oxidation of primary alcohols into the corresponding carbonyl compounds was carried out [32]. Benzyl alcohol was selected as a model substratefor oxidation process. As an initial test, different amounts of complex from 0.01 to 0.05 g in acetonitrile solvent were mixed with 30 μL of hydrogen peroxide (30%) as an oxidant and benzyl alcohol(0.5 mmol, 0.05 g) was added to the mixture at room temperature. Also, the reaction was run in the absence of catalyst. Then, bychanging of parameters such as the amount of oxidant from 30to 65 lL and temperature from 20 to 70 °C, optimized conditionsfor oxidation of benzyl alcohol to benzaldehyde was evaluated. After finding the optimized conditions for benzyl alcohol, oxidation of its derivatives and hexanol (0.5 mmol substrate) were studied inthe same way. The reaction progress was monitored by TLC in aregular alternative time. After completion of the reactions and removing of the solvent, the hemogeneous catalyst was separated from the reaction mixture by addition of water (5.0 mL). Then, the organic phase was separated by addition of chloroform (10.0 mL)and dried over Na2SO4. The product was purified by chromatographyon silica gel (ratio of eluent: hexane/ethyl acetate from 1:10 to1:5). Yields were obtained by weighting of isolated products. All products were known by MS and 1H NMR spectroscopy [9,24]. |
| 93% |
With 1-methyl-1H-imidazole; [2,2]bipyridinyl; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; tetrakis(acetonitrile)copper(I) trifluoromethanesulfonate; sodium chloride In neat (no solvent) Milling; Green chemistry; |
General procedure to prepare carbonyl compounds 2a-v.
General procedure: 2,2,6,6-Tetramethylpiperidine 1-oxyl (TEMPO, 9.4 mg,0.06 mmol, 3 mol %), 2,2′-bipyridyl (9,4 mg, 0.06 mmol,3 mol %), [Cu(CN)4]OTf (22.6 mg, 0.06 mmol, 3 mol %) and1-methylimidazole (NMI, 11.5 mg, 11.2 μL, 0.14 mmol,7 mol %) were placed in a zirconia-milling beaker (45 mL)equipped with four balls (two balls × 5 mm , two balls ×12 mm ) of the same material. The jar was sealed and ballmilled for 1 min. Then, benzyl alcohol (216.3 mg, 207 μL,2.0 mmol), NaCl (1.0 g) together with other two zirconia balls(12 mm ) were added and the reaction mixture was subjectedto grinding for further 10 minutes overall (two cycles of5 minutes each). The first milling cycle was followed by a breakof 2 min leaving in the meantime the uncovered jar in open air.The progress of the reaction was monitored by TLC analysis(heptane/AcOEt 9:1 v/v) and GC-MS analysis on an aliquot ofthe crude. Upon completion of the ball milling process, the jarwas opened, the milling balls were removed and the resultingcrude product (adsorbed on NaCl) was then easily transferredinto a separating funnel filled with an aqueous 10% citric acidsolution (20 mL). The aqueous phase was extracted withcyclopentyl methyl ether (or alternatively with AcOEt)(3 × 15 mL). The combined organic fractions were washed withH2O (25 mL) and brine (25 mL), then dried over Na2SO4, andconcentrated in vacuo to give benzaldehyde in high yield (195 mg, 92%) and good purity (>93% by GC analysis). Alternatively, after completion of the reaction, the resulting crudeproduct (adsorbed on NaCl) can be also easily purified by ashort column chromatography on silica gel using heptane/ethylacetate (9:1 v/v) as the eluents to afford pure aldehyde 2b inhigh yield (202 mg, 95%) as a colourless liquid. |
| 93% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical In aq. buffer at 40℃; for 8h; |
|
| 93% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; copper (II) dichloro(N,N,N',N'-tetramethylethylenediamine) In acetonitrile at 25℃; for 3h; chemoselective reaction; |
2.3. Typical procedure for the Aerobic oxidation of alcohols using CuCl2/TMEDA/TEMPO2.3. Typical procedure for the Aerobic oxidation of alcohols using CuCl2/TMEDA/TEMPO
General procedure: Method A: A 20-mm culture tube with capacity to 15 mL andequipped with a magnetic stirrer was loaded with MeCN (2 mL), CuCl2(3.0 × 10 3 mmol, 0.4 mg) and TMEDA (3.0 × 10 3 mmol, 0.45 μL). Tothis slightly greenish blue solution, alcohol 1b (3 mmol, 320 μL) andTEMPO (3.0 × 10-2 mmol, 4.7 mg, 1.0 mol%) were added at roomtemperature (25 C). The opened flask reaction was stirred at 25 Cunder bubbled air (see apparatus on SI) where within 2 h, the totalconversion of 1b was confirmed by GC/FID. Then, the crude was filteredoff in a minimal amount of silica gel (ca. 10 mg) furnishing 353 mg ofthe pure p-tolualdehyde (2b) in 98 % of yield.Method B: Into a 20-mm culture tube with capacity to 15 mL andcharged with a solution of the alcohol 1b (3 mmol, 320 μL) in MeCN(2 mL), were sequentially added TEMPO (300 μL of a 0.1 M solution inacetonitrile, 1.0 mol%) and CuCl2/TMEDA (15 μL of a 0.1 M solution inacetonitrile, 0.1 mol%) via syringe in one portion. The reaction wasstirred at 25 C under bubbled atmospheric air in an opened flask andmonitored by GC/FID, where within 2 h, the total conversion of 1b wasconfirmed. Finally, the crude material was filtered off in a minimalamount of silica gel (ca. 10 mg) furnishing 2b in 98 % of yield. Thereactions using either Method A or Method B were able to produce 2bwith the same yield. A detailed solvent effect study and a scalable procedurecan be found in S.I. Moreover, the values of TON/TOF/E-factorare given in the Table 2. |
| 92% |
With glacial acetic acid; 1-hydroxy-3H-benz[d][1,2]iodoxole-1,3-dione In acetonitrile at 20℃; for 8h; |
|
| 92% |
With silver nano particles dispersed dispersed water extract of fly ash at 70℃; for 5.5h; Inert atmosphere; Green chemistry; |
|
| 92% |
With dihydrogen peroxide In lithium hydroxide monohydrate at 20℃; for 10h; Green chemistry; |
|
| 92% |
With sulfur(VI) fluoride; potassium carbonate; dimethyl sulfoxide at 20℃; for 12h; chemoselective reaction; |
|
| 92% |
With potassium hydroxide In toluene at 110℃; for 6h; |
|
| 92% |
With tert.-butylnitrite at 80℃; for 6h; Inert atmosphere; Schlenk technique; Sealed tube; |
|
| 91% |
With sodium tetrahydridoborate; oxygen; potassium carbonate In methanol; lithium hydroxide monohydrate at 20℃; for 0.5h; |
|
| 91% |
With sodium tetrahydridoborate; 1% Pd/C; lithium hydroxide monohydrate; oxygen; potassium carbonate In ethanol at 20℃; for 0.5h; |
|
| 91% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; anhydrous sodium carbonate; <i>L</i>-proline; copper(II) bromide In methanol at 20℃; for 6h; |
|
| 91% |
With oxygen; potassium carbonate In toluene at 90℃; for 10h; |
|
| 91% |
With [ReOCl3(PPh3)2]; 4,4’-dichlorodiphenyl sulfoxide In toluene for 24h; Reflux; |
General procedure for the oxidation of alcohols catalyzed by ReOCl3(PPh3)2 using bis(4-chlorophenyl) sulfoxide as oxidant agent
General procedure: To a solution of ReOCl3(PPh3)2 (0.083 g, 0.1 mmol) in toluene (3 mL) was added the bis(4-chlorophenyl) sulfoxide (0.271 g, 1 mmol) and the alcohol (1.0 mmol). The reaction mixture was heated at reflux temperature in air (the reaction times are indicated in Tables 1-4) and the progress of the reaction was monitored by TLC. Upon completion, the reaction mixture was evaporated and purified by silica gel column chromatography with n-hexane to afford carbonyl compounds and bis(4-chlorophenyl) sulfide, which are all known compounds and their 1H NMR and 13C NMR data are consistent with those of the commercial products. |
| 91% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; C110H202N8O47; oxygen; copper(II) bis(trifluoromethanesulfonate); potassium carbonate In lithium hydroxide monohydrate at 20℃; for 18h; Green chemistry; |
General procedure for aerobic oxidation of alcohols in water
General procedure: To a 48 mL tube, were added Cu(II) or Cu(I) salt (0.05 mmol), PEG-PyTa (0.025 mmol) and H2O (3.0 mL). The mixture was stirred for 30 min at room temperature and a clear dark-blue solution was observed. Then alcohols (1.0 mmol), TEMPO (0.05 mmol), and K2CO3 (0.2 mmol) were sequentially added, followed by connecting a balloon of oxygen. The reaction mixture was stirred at room temperature until the reaction completed based on GC analysis. After that, the reaction mixture was extracted with MTBE (3 mL×3) and the extracts were combined, dried over anhydrous Na2SO4 and concentrated under vacuum. Finally, the residue was purified by flash chromatography on silica to afford the desired aldehydes. |
| 91% |
With melamine-(H2SO4)3; C3H6N6*3HNO3; lithium hydroxide monohydrate; potassium bromide In neat (no solvent) Green chemistry; |
|
| 91% |
With 3Co(2+)*2C21H9NO8(4-)*2H2O*2C2H8N(1+)*2C3H7NO; <i>L</i>-proline In acetonitrile at 20℃; for 3h; |
|
| 90% |
With dihydrogen peroxide In lithium hydroxide monohydrate; acetonitrile at 90℃; for 1.58333h; |
|
| 90% |
With sym-collidinium chlorochromate; orthoperiodic acid In acetonitrile at 20℃; for 0.0833333h; |
Typical procedure for the oxidation alcohols to aldehydes and ketones using periodic acid catalyzed by S-COCC
General procedure: A solution of acetonitril (10 mL, 1mmol) and periodic acid was placed in flask and stir for the 15 min. Then, a mixture of alcohols (1mmol) and S-COCC (1%mmol) was added and the resulting mixture was stirred at room temperature for a suitable period (Table 3) and completion of the reaction investigated byTLC (n-hexane/EtOAc; 2:1) analysis. Then, EtOAc (20ml) was subjoined to the reaction mixture and after being washed with water/sodium solfite (1:1), the mixture was filtered off. The solvent was vaporized and produced pure products. |
| 90% |
With 1-methyl-1H-imidazole; copper (I) iodide; C20H25N4O2 In acetonitrile at 25℃; for 3h; |
|
| 90% |
With ferric(III) bromide; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; benzotrifluoride; L-phenylalanine; oxygen for 24h; Reflux; Green chemistry; |
4 Example 4
Equipped with a magnetic stirrer in round bottom flask methyl benzyl alcohol (12. 22g, 100. Ommol, namely formula The R1 is 4-methyl, R2 is hydrogen, X is carbon, η is 1, m is 0), ferric chloride (0. 81g, 5mmol), L- isoleucineAcid (1.31g, 10mmol), TEMP0 (1.56g, 10mmol), toluene 300. OmL was added , then the reaction with oxygen in the air bottleReplacement, stirred and reflux for 6h. After completion of reaction, the reaction mixture was cooled to room temperature, filtered, the filtrate evaporated to give the crude product,The resultant crude product was purified by column chromatography, with n-hexane: Elution: (10 1 volume ratio) mixed liquid of ethyl acetate containing the desired collectionLabeled compound of the eluent, evaporation of the solvent and dried to give the product p-tolualdehyde 10. 93g, 91% yield. p-fluorophenyl methanol (1. 26g, 10. Ommol, i.e., of formula (I), R1 is 4-fluoro, R2 is hydrogen, XCarbon, η is l, m is 0) is added and experimental methods and procedures were the same as in Example 1, except that: iron bromide (0. 03g, 0 lmmol),L_ phenylalanine (0. 17g, 1. Ommol), ΤΕΜΡ0 (0. 31g, 2. Ommol), benzotrifluoride 30. OmL, the reaction with oxygen bottlesAfter stirring at reflux the air is purged 24h. To give the final product 1. 14g, yield 90%. |
| 90% |
With ammonium hydroxide; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; copper(II) oxide at 60℃; for 24h; |
4 Example 1:
General procedure: In a 150 mL thick-walled pressure tube equipped with a magnetic stirrer,In an air atmosphere,To the system was added benzyl alcohol (i.e., R1 in formula (I) H) 1.0 mmol (108.1 mg)Ammonia (1.6 x 10-2 mol / L) 5.0 mL,5 mol% (9.5 mg) of cuprous iodide,TEMPO 5 mol% (7.8 mg),100 & lt; 0 & gt; C for 12 h,After the reaction is over,The reaction solution was cooled to room temperature,And extracted with ethyl acetate (3 x 5.0 mL). The organic layers were combined and concentrated in vacuo to remove ethyl acetate to give the crude product. The crude product was purified by column chromatography(Petroleum ether: ethyl acetate = 10: 1) to give the pure desired product.The yield of 97.6 mg was 92%. |
| 90% |
With iron (ΙΙΙ) nitrate nonahydrate; oxygen; 2,3-dicyano-5,6-dichloro-p-benzoquinone In 1,2-dichloro-ethane at 60℃; for 3h; Schlenk technique; Green chemistry; |
|
| 90% |
With 5H3N*5H(1+)*IMo6O24(5-); oxygen; sodium chloride In lithium hydroxide monohydrate; acetonitrile at 70℃; for 20h; Green chemistry; |
|
| 90% |
With ammonium hydroxide; copper (I) iodide; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical In lithium hydroxide monohydrate for 24h; Reflux; Green chemistry; |
|
| 90% |
With 1,1,2,2-tetrahydroperoxy-1,2-diphenylethane; hydrogen bromide; glacial acetic acid In lithium hydroxide monohydrate at 40℃; for 0.733333h; |
Selective metal free oxidation of secondary, benzylic and allylic alcohols to corresponding carbonyl compounds (Scheme 2, entry 11) General procedure
General procedure: A solution of alcohol (1 mmol), HOAc (0.1 mmol), HBr (0.5 mmol) and THPDPE (1 mmol) was stirred at 40 oC. After the completion of the reaction as followed by TLC, the mixture was quenched with Na2SO3 (3M, 1mL) and the products were extracted using CH3Cl (35 mL). For more purification, silica- packed column chromatography (hexane-EtOAc) was applied. Products were characterized on the basis of their melting points, elemental analysis and IR, 1H-NMR, and 13C-NMR spectral analysis. |
| 89% |
With potassium peroxodisulfate at 50℃; for 0.166667h; Ionic liquid; |
|
| 89% |
With potassium carbonate In lithium hydroxide monohydrate; dimethyl sulfoxide at 60℃; for 0.5h; |
|
| 89% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; [Cu2(1,2-benzenedicarboxylate)2(1,4-bis(1,2,4-triazol-1-ylmethyl)-2,3,5,6-tetrafluorobenzene)2]·3H2O}n; anhydrous sodium carbonate In acetonitrile at 75℃; for 16h; |
2.2 Catalytic reaction
General procedure: In a typical experiment, 4-methoxybenzyl alcohol (12μL, 0.1mmol), Cu-FMOF (11.3mg, 10mmol %), TEMPO (7.8mg, 0.05mmol) and NaCO3 (10.6mg, 0.1mmol) in 1mL of air saturated acetonitrile were taken in a 15-mL three-necked round-bottom flask. The solution was magnetically stirred for 16h at 75°C under air atmosphere. The progress of the reaction was monitored via gas chromatography (Shimadzu GC-2010AF) involving a Chromopak capillary column and flame ionization detector. The products were further confirmed by using gas chromatography-mass spectroscopy (GC-MS) (Shimadzu GCMS-2010). The concentrations of 4-methoxybenzyl alcohol and 4-methoxybenzylaldehyde were calibrated by external standard method with standard samples (see Fig. S1). |
| 89% |
With aluminum(III) oxide; [Ru(2,2′-bipyridine)2(2,2′-bipyridine-5,5′-dicarboxylic acid)Cl2]; oxygen In acetonitrile for 12h; Irradiation; |
|
| 89% |
With C12H17N2O(1-)*Cu(2+)*N3(1-); dihydrogen peroxide In acetonitrile at 80℃; for 2h; |
|
| 88% |
With urea hydrogen peroxide addition compound; 1-n-butyl-3-methylimidazolium tetrafluoroborate; magnesium(II) bromide at 60℃; for 2h; |
|
| 88% |
Stage #1: 4-fluorobenzylic alcohol With cobalt ferrite nanoparticles In lithium hydroxide monohydrate for 0.0333333h;
Stage #2: With oxone In lithium hydroxide monohydrate at 20℃; for 0.583333h; |
General Procedure for the Oxidation of Alcohol
General procedure: Alcohol (1 mmol), water (1 mL), and CoFe2O4 MNPs (11.8mg, 5 mol %) were added to a round-bottomed flask. The reaction mixture was stirred for the two minutes, and then oxone (0.6 mmol) was added in three portions. The reaction mixture was placed at room temperature and stirred for the specified time (Table 5). The reaction was followed by TLC (EtOAc-cyclohexane, 2:10). After the completion of the reaction, the product was extracted in dichloromethane. The solvent was evaporated under reduced pressure to give the corresponding aromatic products. Purification of the residue using plate chromatography (silica gel) provided the pure carbonyl compounds. The aliphatic products in dichloromethane was dried with anhydrous MgSO4 and detected by GC-FID. |
| 88% |
With oxygen In ethanol at 80℃; for 30h; |
|
| 88% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; C12H8Cl3FeN2O4Zr4; oxygen; NaNO2 In acetonitrile at 20℃; for 12h; |
|
| 88% |
With potassium peroxomonosulfate In lithium hydroxide monohydrate at 20℃; for 1.16667h; |
|
| 88% |
With double-atom catalyst FeCo-DAC In o-dimethylbenzene at 140℃; for 36h; Inert atmosphere; Sealed tube; |
|
| 87% |
With N-iodo-succinimide In benzene for 2.5h; Irradiation; |
|
| 87% |
With copper(II) dichloride dihydrate; oxygen; Cs2CO3 In toluene at 40℃; for 12h; |
|
| 87% |
With C30H56AgN4(1+)*C2F3O2(1-); potassium-t-butoxide In toluene at 20℃; for 4h; Darkness; |
|
| 87% |
With (NH4)4[CuMo6O18(OH)6]·5H2O; oxygen; sodium chloride In lithium hydroxide monohydrate; acetonitrile at 60℃; for 20h; |
|
| 87% |
With iron (ΙΙΙ) nitrate nonahydrate; TEMPOL; oxygen; oxalic acid In lithium hydroxide monohydrate at 50℃; for 4h; |
5 Example 5: Synthesis of p-fluorobenzaldehyde
In an oxygen atmosphere, sequentially add Fe(NO3)3·9H2O (97.0 mg, 0.24 mmol), H2C2O4·2H2O (30.3 mg, 0.24 mmol) into the reaction flask,4-OH-TEMPO (41.3 mg, 0.24 mmol), add 2 mL H2O after regular stirring,P-Fluorobenzyl alcohol (381.4 mg, 3 mmol) was reacted at 50 for 4 h. After the reaction,Sodium chloride is added to the mixture for salting out. After filtration, it was extracted with 12 mL of ethyl acetate,Drying with anhydrous sodium sulfate and purifying by column chromatography (using a mixed solvent of ethyl acetate/petroleum ether volume ratio of 1:10 as eluent), the yield is 87%. |
| 86% |
With ferric(III) chloride; HNO3 In propan-2-one at 20℃; for 0.333333h; Sonication; |
|
| 86% |
With 4-dimethylaminopyridine; 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; copper (II) acetate In neat (no solvent) at 25℃; for 24h; Green chemistry; |
|
| 86% |
With oxygen In N,N-dimethyl-formamide at 100℃; for 6h; |
|
| 86% |
With 2C36H60N9(3+)*3O4W(2-); dihydrogen peroxide In lithium hydroxide monohydrate at 20℃; for 0.216667h; Green chemistry; |
|
| 85% |
With cerium(III) sulphate; barium bromate In lithium hydroxide monohydrate; acetonitrile for 3.3h; Heating; |
|
| 85% |
With mesoporous silica at 20℃; for 0.166667h; |
|
| 85% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; Sodium hydrogenocarbonate In dichloromethane; lithium hydroxide monohydrate at 20℃; for 6h; Green chemistry; chemoselective reaction; |
The procedure for the oxidation of benzyl alcohol is as follows:
General procedure: A mixture of H2O (5 mL) and CH2Cl2 (5 mL) wasadded to the chlorinated polymeric beads (2 g). (The unchlorinated beads were obtained from HaloSource, Inc. The unchlorinated beads were chlorinated by soaking the beads in bleach solution, with pH adjusted to 7 by additionof AcOH, for an hour. Then, the chlorinated beads were filtered and dried in air.) After addition of TEMPO (10 mg,0.064 mmol) and benzyl alcohol (0.2 g, 1.8 mmol), NaHCO3(0.5 g) was added to the mixture. The mixture was stirred at r.t. for 3 h and filtered. The residue on the filter paper was washed with H2O (20 mL) and CH2Cl2 (10 mL), and the organic phase of the filtrate was separated, dried over MgSO4, and filtered. The solvent was removed under vacuum to obtain benzaldehyde. |
| 85% |
With triphenylmethyl alcohol; iron(III) trichloride hexahydrate at 55℃; for 1h; Microwave irradiation; |
General procedures for the synthesis of benzaldehydes
General procedure: The benzyl alcohols substrates (1a-1p) (0.2mmol), FeCl3·6H2O (0.002mmol, 5.4mg) and triphenylmethanol 2 (0.2mmol, 52mg) were mixed in a dried vessel. Then the reaction was irradiated under the microwave at 55°C for 1h. The crude mixture was purified by a flash column chromatography to afford the benzaldehydes (4a-4p). |
| 85% |
With IBX; (+/-)-camphor sulfonic acid In 1,4-dioxane; dichloromethane at 20℃; Inert atmosphere; |
General procedure
General procedure: Under nitrogen atmosphere, 1.1-1.5 mmol IBX and 10 to 20 mol% (±)-CSA monohydrate was added in round bottom flask already charged with magnetic bar and 2 mL DCM:1,4-Dioxane. Stirred the mixture for 10 minutes at room temperature and added the solution of alcohol dropwise for 5 minutes. Stirred the solution at room temperature till complete consumption of alcohol. Strip off the solvent and dilute the reaction mass with DCM. Filter the suspension through sintered funnel and wash the residue properly with DCM. This residue (white powdered solid, reduced part of IBX) was successfully used for preparation of IBX. Concentrate the filtrate on rotavapor and purify the product by column chromatography. |
| 84% |
With oxygen; potassium hydroxide In toluene at 100℃; for 18h; |
|
| 84% |
With potassium peroxodisulfate; V2O5/TiO2 In lithium hydroxide monohydrate; acetonitrile at 80℃; Sealed tube; Green chemistry; |
|
| 84% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; oxygen; copper (II) acetate; diethylamine In acetonitrile at 50℃; for 5h; chemoselective reaction; |
General procedure for synthesis of carbonyl compounds
General procedure: A mixture of an alcohol (5.0 mmol), Cu(OAc)2*H2O (50 mg, 5 mol%), TEMPO (39 mg,5 mol%) and diethylamine (25 μL, 5 mol%) in CH3CN (10 mL) was stirred at 50°C under oxygen balloon for a specified time as noted in the Table I. For the analysis of the products, gas chromatography (equipped with a Capillary Column of VF-1 ms, 15 m,0.25 mm, 0.25 μm) was employed. Time-to-time quantification of the reactants consumed and products generated was examined by GC by comparing the peak area with the standard starting alcohol and the product. After a specified time, the reaction mixture was passed through a celite pad and washed with acetonitrile, and concentrated to get the crude, which was purified by column chromatography (hexane/ethyl acetate = 4.75/0.25) to obtain the desired product. |
| 83% |
With Bromotrichloromethane; [4,4'-bis(1,1-dimethylethyl)-2,2'-bipyridine-N1,N1']bis[2-(2-pyridinyl-N)phenyl-C]iridium(III) hexafluorophosphate In acetonitrile at 20℃; for 24h; Schlenk technique; Irradiation; Inert atmosphere; |
General Procedure for synthesis of product
General procedure: An 25 mL oven-dried Schlenk tube was equipped with a stirring bar, alcohols 1 (0.5 mmol) and Ir(ppy)2(dtbbpy)PF6 (0.005 mmol, 1 mol%). The mixture was degassed by using standard Schlenk techniques with an oil pump. Then MeCN (4 mL) and bromotrichloromethane (0.75 mmol, 1.5 eq) were injected into the reaction tube. The reaction mixture was placed under a 7 W blue LED and stirred at room temperature. After 24 h, the mixture was concentrated under reduced pressure using a rotary evaporator and the purification was done by column chromatography on silica gel (200-300 mesh) with petroleum ether / ethyl acetate as the eluent to give the pure product |
| 82% |
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; oxygen In acetonitrile at 75℃; for 9h; |
|
| 82% |
With 2,2,6,6-tetramethyl-1-piperidinyloxy free radical; NaNO3; europium(III) nitrate hexahydrate; glacial acetic acid In toluene at 40℃; for 9h; |
|
| 82% |
With Ni/Cu (3:1) bimetallic nanoparticles in complex with dendritic ligand 2,4,6-tris(di-4-chlorobenzamido)-1,3-diazine; air In lithium hydroxide monohydrate at 20℃; for 0.5h; Green chemistry; chemoselective reaction; |
General procedure for the selective oxidation of alcohol to the aldehyde using Ni/Cu (3:1) 4c bimetallic NPs as a catalyst
General procedure: In a round-bottom flask, alcohol (1.0 mmol) and Ni/Cu (3:1) 4c of 4.0 mol% catalyst were added to water (5.0 mL) and the mixture was stirred for 30 min at room temperature. The reaction progress and conversion of the reactants were monitored by gas chromatography (GC). The reaction mixture was centrifuged at 4,000 rpm after the complete conversion of alcohol into aldehyde or ketone due to isolating the catalyst and was filtered. Finally, the desired pure products were obtained from the run through silica gel column chromatography (n-hexane/ethylacetate 10:1). |
| 82% |
With oxygen; iron oxide In methanol at 20℃; for 0.5h; Irradiation; |
2.5. Procedure for photocatalytic oxidation of benzyl alcohols
General procedure: The photocatalytic oxidation of benzyl alcohols (BA) to benzaldehydeswith high selectivity in presence of the synthesized Fe2O3-HNTcatalyst was carried out in a photochemical reactor comprising of a 500mL of reaction chamber made up of quartz, surrounded by a 300 WXenon arc lamp along with a UV cut-off filter ( ≥ 420 nm) as the visiblelight source. The light source was encircled by a double-jacketed quartzimmersion by means of a well with an inlet and outlet for water circulationto ensure a safe temperature throughout the photocatalytic process.At first, 25 mg of the catalyst sample was immersed into 20 mL ofmethanol (MeOH) along with 2 mmol of BA in the photocatalytic reactionchamber. The reaction was performed with molecular oxygen(O2) as oxidant and the O2 was passed with a flow rate of 60 mL/min inpresence of light for 30 min. It was done by continual stirring by amagnetic stir placed inside the reactor. The whole photochemical reactionwas completed at RT. The reaction progress was monitoredthrough thin layer chromatography (TLC) using ethyl acetate/n-hexane,1:9. The resultant product i.e., benzaldehyde was separated by utilizingcolumn chromatographic analysis (100-200 mesh silica) with a mixtureof n-hexane and ethyl acetate as eluent. In the same way, the oxidant O2was replaced by 3 mmol of hydrogen peroxide (H2O2), and the reactionwas carried out by adding 2 mmol of BA into 20 mL of acetonitrile(CH3CN) followed by the addition of 25 mg of Fe2O3-HNT at RT. The photoirradiation time was set as 20 min. After 20 min the reaction wasquenched, and benzaldehyde was separated by chromatographic |
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