Oxidation Of Secondary Alcohols Research Articles

Bimetallic Ru(II) Complex Catalysed β‐Alkylation of Secondary Alcohols and α‐Alkylation of Ketones: Selective Formation of Saturated Ketones

AbstractRu(II) bimetallic [(p‐cymene)2(RuCl)2L1]2X (X=BF4 (Cat2); X=PF6 (Cat3)) and monometallic [(p‐cymene)(RuCl)L2]BF4 (Cat4) (where L1=N,N’‐(3,3’,5,5’‐tetraisopropyl‐[1,1’‐biphenyl]‐4,4’‐diyl)bis(1‐(pyridin‐2‐yl)methanimine); L2=N‐(2,6‐diisopropyl‐phenyl)‐1‐(pyridin‐2‐yl)‐methanimine) catalyse selective synthesis of saturated ketones using β‐alkylation of secondary alcohol or α‐alkylation of ketones with primary alcohol. Notably, a single catalyst facilitates the oxidation of both secondary and primary alcohols followed by condensation and hydrogenation yielding α‐alkylated saturated ketones. Remarkably, this system allows catalyst loading as low as 0.01 mol% for β‐alkylation of secondary alcohols and 0.005 mol% for the α‐alkylation of ketone, delivering access to a wide array of α‐alkylated ketones derivatives with yields of ~97 %. Complex Cat2, in particular, orchestrates one‐pot alkylation reactions with a high turnover frequency (TOF) of 5.6 105 h−1 using as low as low catalyst loading of 0.0001 mol%. A comparative study between bimetallic and monometallic complexes reveals that complex Cat2 exhibits better selectivity for the formation of saturated ketones presumably owing to a cooperative effect between the metal centres. The scale‐up synthesis highlights the practical applicability of the catalytic approach. To delve into the plausible mechanisms, we conducted initial investigations through meticulously controlled experiments and spectroscopic analysis.

Reusable Magnetite Nanoparticle (Fe3O4 NP) Catalyst for Selective Oxidation of Alcohols under Microwave Irradiation.

Iron oxide nanoparticles (NPs) are nontoxic and abundant materials which have long been investigated as reusable catalysts in oxidation reactions, but their use so far has been hampered by a low selectivity. Here, unsupported iron oxide NPs have been found to successfully catalyze the microwave-assisted oxidation of primary and secondary alcohols to their respective aldehydes and ketones with a high selectivity when N-methylmorpholine N-oxide was used as the terminal oxidant. The crystalline phase and size of the iron-based catalyst have a drastic effect on its activity, with small magnetite (Fe3O4) NPs being the optimal catalyst for this reaction. The nanocatalyst could be easily recovered by magnetoseparation and successfully recycled four times without any need for special pretreatment or reactivation step and with a minimal loss of activity. The subsequent loss of activity was attributed to the transition from magnetite (Fe3O4) to maghemite (γ-Fe2O3), as confirmed by X-ray diffraction, Fourier transform infrared, and X-ray absorption near-edge spectroscopy. The nanocatalyst could then be reactivated by the high-temperature microwave treatment and used again for the microwave-assisted oxidation reaction.

A new perspective for palladium(II)-catalyzed alcohol oxidation in aerobic means

The development of alternative and environmentally safe routes for the oxidation of primary and secondary alcohols has attracted the attention of several researchers due to the importance of these oxidized products in industries. Thereby, the oxidation of β-citronellol, geraniol, nerol, borneol, isoborneol, cinnamic alcohol, and benzyl alcohol is described herein. These reactions occurred in an aerobic environment, with or without system pressurization. Acetonitrile was the solvent used. The process was catalyzed by the bimetallic complex formed with palladium(II) acetate and copper(II) acetate, using p-benzoquinone as a cocatalyst in some reaction conditions. The applied system obtained 62.5 points on the eco-scale, with yields above 61%. Alcohol oxidation products are of great importance in industrial applications. Thus, this work presents a cleaner, more sustainable alternative to alcohol oxidations.

A manganese-based catalyst system for general oxidation of unactivated olefins, alkanes, and alcohols.

Non-noble metal-based catalyst systems consisting of inexpensive manganese salts, picolinic acid and various heterocycles enable epoxidation of the challenging (terminal) unactivated olefins, selective C-H oxidation of unactivated alkanes, and O-H oxidation of secondary alcohols with aqueous hydrogen peroxide. In the presence of the in situ generated optimal manganese catalyst, epoxides are generated with up to 81% yield from alkenes and ketone products with up to 51% yield from unactivated alkanes. This convenient protocol allows the formation of the desired products under ambient conditions (room temperature, 1 bar) by employing only a slight excess of hydrogen peroxide with 2,3-butadione as a sub-stoichiometric additive.

Synthesis and catalytic activity of tetradentate β-diketiminato rare-earth metal monoalkyl complexes in tandem Oppenauer oxidation and cross-aldol condensation.

A series of unsymmetric tetradentate β-diketiminato rare-earth metal monoalkyl complexes were synthesized, and their catalytic behavior has been well developed. Indole-incorporated β-diketiminato proligands H2L (L = MeC(NDipp)CHC(Me)NCH2CH2-3-(1-R-C8H4N), R = CH2-(2-C4H7O), L1; R = (CH2)2OMe, L2; Dipp = 2,6-iPr2C6H3) were prepared by the reaction of an arylamino-enone with 1-substituted-tryptamine in good yields. Treatment of the proligands with the rare-earth metal trialkyl complexes RE(CH2SiMe3)3(THF)2 generated the corresponding unsymmetric N,N,C,O-tetradentate β-diketiminato rare-earth metal monoalkyl complexes LRE(CH2SiMe3) (L1, RE = Y (1a), Gd (1b), Yb (1c), Lu (1d); L2, RE = Y (2a), Gd (2b), Yb (2c), and Lu(2d)). During the process, the activation of the sp2 C-H bond at the 2-position of the indole ring led to the formation of an unprecedented β-diketiminato dianion L2-, bonding to the rare-earth metal ions in a chelating N,N,C,O-tetradentate manner. Further studies indicated that these tetradentate rare-earth metal complexes could initiate the Oppenauer oxidation of secondary alcohols into the corresponding ketones in high yields. In the case of primary alcohols, a tandem Oppenauer oxidation and cross-aldol condensation occurred unexpectedly. Various α-mono-substituted benzylidene acetones, α,α'-bis-substituted benzylidene acetones and cyclohexanones were obtained under mild conditions only by controlling the molar ratio of alcohols to ketones. Notably, all these alkenylation ketones exhibited exclusive E configuration.

Graphene as a Platform in Surface-Enhanced Infrared Absorption Spectroscopy (SEIRAS) for Amino-TEMPO Electro-Grafting

2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) has emerged as an environmentally benign catalyst for the electrochemical oxidation of primary and secondary alcohols to aldehydes and ketones (1). This simple organic free radical reagent possesses high activity, and versatility, and is one of the most promising alternatives to noble metal catalysts that were previously studied. The catalytic activity and reactivity of TEMPO is mostly studied in bulk solutions, for fuel cells, aqueous redox flow batteries and sensors (2, 3). For more practicality, various approaches were developed to immobilize TEMPO on active supports, such as anionic polyelectrolytes, and the electropolymerization of TEMPO-substituted pyrrole or thiophene (4, 5). However, these substrates suffer from instability, loss of catalytic activity, degradation of the polymer film in alkaline environment mostly used for TEMPO regeneration. One other way, is to use carbon-based substrates that are stable in aqueous acid and base environment, as well as non-aqueous solutions and have shown enhanced electrocatalytic behavior (6, 7).In this work, we studied the electro-grafting of amino-TEMPO on graphene using in-situ attenuated total reflection infrared absorption spectroscopy (ATR-IRAS). We observed that TEMPO is attached on the surface through covalent bonding between the amine and the graphene lattice, as previously reported (6, 7). While grafting was successfully demonstrated via the oxidation of the primary amine to a radical cation which reacted with the graphene surface, ATR-surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) provided additional spectral feature confirming TEMPO grafting through plasmon induced signal enhancement. Hickey, D. P.; Milton, R. D.; Chen, D.; Sigman, M. S.; Minteer, S. D., TEMPO-Modified Linear Poly(ethylenimine) for Immobilization-Enhanced Electrocatalytic Oxidation of Alcohols. ACS Catalysis 2015, 5 (9), 5519-5524. Mishra, A.; Kim, J.; Zorigt, M.; Romo, A. I. B.; Gaddam, R.; Braun, J. E.; Ziviani, D.; Rodríguez-López, J., Highly Selective TEMPO Catalyzed Bulk Electrooxidation of Isopropanol to Acetone for Application in Electrochemical Heat Pumping. ACS Sustainable Chemistry & Engineering 2023, 11 (16), 6241-6249. Elouarzaki, K.; Mandoc, L.-R. P.; Gorgy, K.; Holzinger, M.; Amarandei, C.-A.; Ungureanu, E.-M.; Cosnier, S., Synthesis and electrochemical characterization of original “TEMPO” functionalized multiwall carbon nanotube materials: Application to iron (II) detection. Electrochemistry Communications 2015, 60, 131-134. Belgsir, E. M.; Schäfer, H. J., Selective oxidation of carbohydrates on Nafion®–TEMPO-modified graphite felt electrodes. Electrochemistry Communications 2001, 3 (1), 32-35. Grimshaw, J.; Perera, S. D., Poly(pyrrole-pyromellitimide) modified electrodes. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 1990, 278 (1), 279-286. Barman, K.; Askarova, G.; Jia, R.; Hu, G.; Mirkin, M. V., Efficient Voltage-Driven Oxidation of Water and Alcohols by an Organic Molecular Catalyst Directly Attached to a Carbon Electrode. Journal of the American Chemical Society 2023, 145 (10), 5786-5794. Yuan, B.; Xu, C.; Zhang, D.; Zhang, R.; Su, H.; Guan, P.; Nie, J.; Fernandez, C., Electrografting of amino-TEMPO on graphene oxide and electrochemically reduced graphene oxide for electrocatalytic applications. Electrochemistry Communications 2017, 81, 18-23.

Immobilization of enzymes on functionalized cellulose nanofibrils for bioremediation of antibiotics: Degradation mechanism, kinetics, and thermodynamic study

The deteriorating environmental conditions due to increasing emerging recalcitrant pollutants raised a severe concern for its remediation. In this study, we have reported antibiotic degradation using free and immobilized HRP. The functionalized cellulose support was utilized for efficient immobilization of HRP. Approximately 13.32 ± 0.52 mg/g enzyme loading was achieved with >99% immobilization efficiency. The higher percentage of immobilization is attributed to the higher surface area and carboxylic groups on the support. The kinetic parameter of immobilized enzymes was Km = 2.99 mM/L for CNF-CA@HRP, which is 3.5-fold more than the Michaelis constant (Km = 0.84794 mM/L) for free HRP. The Vmax of CNF-CA@HRP bioconjugate was 2.36072 mM/min and 0.558254 mM/min for free HRP. The highest degradation of 50, 54.3, and 97% were achieved with enzymatic, sonolysis, and sono-enzymatic with CNF-CA@HRP bioconjugate, respectively. The reaction kinetics analysis revealed that applying ultrasound with an enzymatic process could enhance the reaction rate by 2.7–8.4 times compared to the conventional enzymatic process. Also, ultrasound changes the reaction from diffusion mode to the kinetic regime with a more oriented and fruitful collision between the molecules. The thermodynamic analysis suggested that the system was endothermic and spontaneous. While LC-MS analysis and OTC's degradation mechanism suggest, it mainly involves hydroxylation, secondary alcohol oxidation, dehydration, and decarbonylation. Additionally, the toxicity test confirmed that the sono-enzymatic process helps toward achieving complete mineralization. Further, the reusability of bioconjugate shows that immobilized enzymes are more efficient than the free enzyme.

Catalysis via bimetallic Pd-Sn nanoparticles: green oxidation of secondary benzyl alcohol in water in the absence of base

Catalysis via bimetallic Pd-Sn nanoparticles: green oxidation of secondary benzyl alcohol in water in the absence of base

Mesoporous MCM-41@SnPr-Kryf.23-Mn a versatile and reusable nanocatalyst for the oxidation of primary and secondary alcohols in the presence of hydrogen peroxide as oxidant

Mesoporous MCM-41@SnPr-Kryf.23-Mn a versatile and reusable nanocatalyst for the oxidation of primary and secondary alcohols in the presence of hydrogen peroxide as oxidant

Transition-Metal-Catalyzed C-C Bond Formation from C-C Activation.

ConspectusC-C single bonds are ubiquitous in organic compounds. The activation and subsequent functionalization of C-C single bonds provide a unique opportunity to synthesize conventionally inaccessible molecules through the rearrangement of carbon skeletons, often with a favorable atom and step economy. However, the C-C bonds are thermodynamically and kinetically inert. Consequently, the activation of C-C bonds is particularly attractive yet challenging in the field of organic chemistry. In the past decade, we sought to develop efficient strategies to carry out transition-metal-catalyzed diverse C-C cleavage/C-C forming reactions and to obtain some insights into the intrinsic reactivities of different C-C bonds. With our efforts, readily available alcohols, carboxylic acids, and ketones served as suitable substrates for the catalytic C-C coupling reactions, which are reviewed in this Account. In 2009, we observed a Ni-catalyzed cross coupling of aryl nitriles with arylboronic esters through C-CN cleavage. Encouraged by these results, we are interested in transition-metal-catalyzed C-C bond activation. Due to their broad availability, we then turned our attention to C-C cleavage of carboxylic acids. Rhodium-catalyzed decarbonylative coupling of carboxylic acids with (hetero)arenes was then achieved through oxidative addition of in situ formed, more reactive mixed anhydrides to Rh(I) without the need for oxidants that are commonly required for the decarboxylative coupling of carboxylic acids. Subsequently, the decarbonylation of more challenging unstrained aryl ketones was realized under Rh catalysis assisted by N-containing directing groups. Following this work, a group exchange of aryl ketones with carboxylic acids was achieved through 2-fold C-C bond cleavage. By employing the chelation strategy, Rh-catalyzed C-C bond activation of secondary benzyl alcohols was also accomplished through β-carbon elimination of the rhodium alcoholate intermediates. The competing oxidation of secondary alcohols to ketones via β-hydrogen elimination of the same intermediates was suppressed as thermodynamically favorable five-membered rhodacycles are formed after β-carbon elimination. Different types of transformations of alcohols, including the Heck-type reaction with alkenes, cross coupling with arylsilanes, and Grignard-type addition with aldehydes or imines, have been achieved, showing the great potential of secondary alcohols in the formation of C-C bonds. These C-C bond-forming reactions are complementary to traditional cross couplings of aryl halides with organometallic reagents. However, these transformations produce small molecules as byproducts. To improve the atom economy, we then investigated C-C bond transformations of strained-ring cyclic compounds. Ni-catalyzed intermolecular cyclization of benzocyclobutenones with alkynes was recently achieved via the uncommon cleavage of the C1-C8 bond by employing a removable blocking strategy. Rh-catalyzed intramolecular annulation of benzocyclobutenols with alkynes was also achieved. In summary, our developments demonstrate the great potential of transition-metal-catalyzed C-C bond activation for the formation of new C-C bonds. To further expand the synthetic utility of C-C bond activation, more efforts are required to expand the substrate scope and to achieve earth-abundant metal-catalyzed transformations.

The Chemistry of Hager’s Test for Brucine

The purpose of the article is clear up what is happening in the test tube during the Hager’s test for brucine, that is, throughout the interaction of brucine with manganese dioxide in acidic medium. The paper is a Theoretical Organic Chemistry Study based on the chemical deportment of reagent and substrate, in accordance with the reaction medium. A series of reactions occur during the test: electrophilic attack to double bond, acidolysis of organometallic intermediates, oxidation of secondary alcohol to ketone, acid catalysed hydration, reaction of enol, epoxide formation, ring opening, selective reaction of diol, and ring cleavage of seven-member ring. A yellowish-red to blood-red colour is observed after filtering residual black manganese dioxide. This is due to halochromism, present in acidic medium, since there are no chromogenic groupings.

Electron‐Deficient Phenanthrenequinone Derivative for Photoactivated Hydrogen Atom Transfer Mediated Oxidation of Secondary Alcohols

AbstractThe Front Cover image is provided by Juulia Talvitie, University of Helsinki (Finland) and Dr. Juan Cruz Landoni, EPFL (Switzerland). The image illustrates the mechanistic difference between two quinonic photocatalysts, PQ and PQ‐CF3. PQ‐CF3 favors hydrogen atom transfer, whereas PQ is an efficient single electron transfer catalyst. Read the full text of the Research Article at 10.1002/cptc.202300107.

Development of sustainable green catalysts for oxidation of alcohols via decorated palladium nanoparticles on magnetic carbon nanotube/MOF

Using a straightforward method, this study fabricated an eco-friendly low-cost magnetic nanocomposite consisting of magnetic carbon nanotube/MOF as a stabilizer. Pd nanoparticles (Pd NPs) were then decorated on the designed magnetic carbon nanotube/MOF microspheres, and the resulting magnetic carbon nanotube/MOF/Pd NPs nanocomposite were employed as heterogeneous catalysts in Aerobic oxidation of primary and secondary alcohols. The attractiveness of this work is in the selective oxidation of several types of active and inactive alcohol substrates. The most important feature of this catalyst is its successful recovery and simple separation repeatedly without reducing its activity and selectivity. The active surface area of this Nanocatalyst is very large due to its structural properties, and as a result, it provides more available catalytic sites, which increases its activity. The identification techniques used to investigate the structural properties of this Nanocatalyst confirm its successful synthesis and appropriate palladium loading into the catalyst sites. The oxidation of alcohols was determined by Gas Chromatography (GC). The 100% selectivity, excellent turnover number (TON), high yield, almost complete and fast conversion of alcohol to the desired aldehydes and ketones without more oxidation, and easy and no-trouble isolation of product and catalyst are outstanding features of this catalytic system. The use of picolinaldehyde lead to the high loading of Pd NPs, reducing the catalyst content needed for the reaction. Regarding the high catalyst loading, using a small amount of catalyst is recommended for proceeding with the reaction efficiently.

Electron‐Deficient Phenanthrenequinone Derivative for Photoactivated Hydrogen Atom Transfer Mediated Oxidation of Secondary Alcohols

AbstractIn 2000, Fukuzumi and co‐workers reported a seminal study on the photochemical oxidation of benzylic alcohols with visible‐light‐excited 9,10‐phenanthrenequinone (PQ) under argon atmosphere (J. Am. Chem. Soc. 2000, 122, 8435). We optimized the reaction conditions they reported and were able to oxidize 1‐(4‐methoxyphenyl)ethanol quantitatively to 4'‐methoxyacetophenone in only 15 min with 10 mol % PQ as a photocatalyst under oxygen. However, we observed a significant decrease in the oxidation rate with more electron‐deficient benzylic alcohols as starting materials. To improve the photooxidation performance, we designed a high‐yielding synthetic route for a novel, more electron‐deficient PQ derivative, 3,6‐bis(trifluoromethyl)‐9,10‐phenanthrenequinone (PQ‐CF3). Its efficiency as a photocatalyst in the fast oxidation of secondary alcohols was demonstrated not only with several electronically diverse benzylic alcohols but also with aliphatic substrates. The comprehensive mechanistic studies based on Hammett plot construction, kinetic isotope experiments, and DFT computations suggest that the mechanistic pathway of the alcohol oxidation is dependent on the electronic properties of both the catalyst and the substrate. As the key mechanistic discovery, we showed that the newly developed PQ‐CF3 operates as a highly efficient hydrogen atom transfer (HAT) catalyst.

Kinetic Studies of the Oxidation of Primary Acyclic and Secondary Cyclic Perfumery alcohols using N- Bromosuccinimide in Alkaline Medium

Kinetic Studies of the Oxidation of Primary Acyclic and Secondary Cyclic Perfumery alcohols using N- Bromosuccinimide in Alkaline Medium

Catalytic Activity of Ti-Modified MCM-41 for Oxidation of Secondary Alcohol with H2O2

Catalytic Activity of Ti-Modified MCM-41 for Oxidation of Secondary Alcohol with H2O2

Degradation of oxytetracycline by iron-manganese modified industrial lignin-based biochar activated peroxy-disulfate: Pathway and mechanistic analysis

In this study, high-performance Fe-Mn-modified industrial lignin-based biochar (FMBC) was successfully prepared to facilitate the efficient degradation of oxytetracycline by its driven sulfate radical-based advanced oxidation process with 90% degradation within 30 min. The results showed that oxygenated functional groups (e. g. hydroxyl, carbonyl, etc.) in industrial lignin-based biochar, the synergistic effect of transition metals Fe and Mn, and defective structures were the active sites for activation of peroxy-disulfate. SO4·− produced during the degradation process assumed a key function. Significantly, 38 intermediates were innovatively proposed for the first time in the system, and oxytetracycline was degraded in 7 ways, including deamidation, demethylation, hydroxylation, secondary alcohol oxidation, ring opening, dehydration, and carbonylation. A new perspective on the application of industrial lignin in the advanced oxidative degradation of organic pollutants was provided by this study.

Dual role of chlorogenic acid as an influential precursor in synthesizing nano‐sized Cu(II) complexes and investigating its catalytic role in the oxidation of alcohols and its antibacterial activity

Chlorogenic acid (3-O-caffeoyl-D-quinic acid) (CGA) is a compound found in a large kind of food, including fruits, vegetables, olive oil, spices, and coffee. CGA has the ability to bind with several metal ions to increase its biological activity. In the last ten years, CGA has attracted considerable attention due to its biological activity like anticancer, antioxidant, and antibacterial. In this present study, we used CGA and Cu(II) for the synthesis of the metal complexes. As a ligand for the synthesis of novel nanoscale Cu(II) complex, the CGA has been used. Then the product was characterized by FT-IR spectroscopy, FESEM, XRD, and EDAX. FESEM image for nanoscale copper(II) complex showed nanoparticles with an average diameter of 40 nm. XRD of synthesized nanoscale copper(II) complex gives characteristic peaks at 2θ°: 33.12, 36.37, 38.77, 48.83, 53.52, 58.82, 63.47, 66.34, and 68.91. Significantly, our product showed remarkable catalytic activity toward the oxidation of primary and secondary alcohols. The antibacterial activity of the final product was assessed against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria using an inhibition zone test. The synthesized nanoscale Cu(II) complex exhibited strong antibacterial activity against both of these bacteria.

Assessment of the metal exchanged phosphomolybdic acid salt-catalyzed nerol oxidation reactions with hydrogen peroxide

In this work, phosphomolybdate salts were synthesized by exchanging the protons of the phosphomolybdic acid with metal cations (i.e., Co2+, Cu2+, Zn2+, Mn2+, Ni2+, Al3+, and Fe3+ cations) and evaluated as catalysts in oxidation reactions of terpene alcohols with hydrogen peroxide. All the catalysts were characterized by Raman, UV-Vis, and infrared spectroscopies, powder X-rays diffraction, energy dispersive spectroscopy, scanning electronic microscopy, and thermal analyses. The strength of the acid sites was determined by potentiometric titration curves. Among the catalysts tested in nerol oxidation (i.e., model molecule selected), AlPMo12O40 was the most active and selective catalyst toward nerol epoxide, the main product. Main reaction variables such as the H2O2: substrate molar ratio, time, temperature, type, and catalyst load were assessed. The focus was to correlate the physicochemical properties of the catalysts with their performance. The reaction scope was extended to other terpene alcohols. Allylic alcohols (nerol and geraniol) were mainly converted to epoxides, while the oxidation of secondary (borneol) and tertiary (linalool) alcohols gave carbonylic products (camphor), or cyclization products (furane and pyrane rings), respectively.

Photocatalytic direct oxygen-isotopic labelings of carbonyls in ketones and aldehydes with oxygen-isotopic waters

Oxygen-isotopic labelings play important roles in identifying and understanding chemical and biological processes. Direct C=O to C=18O or C=17O conversion in a single step leading to labeled compounds can alleviate synthetic burdens without the need for resynthesis. Here we describe a photocatalytic oxygen-isotopic labeling protocol that can efficiently and selectively install 18O and 17O on carbonyls of ketones and aldehydes via oxygen isotope exchange with oxygen-isotopic waters (H218O or H217O) as the sources of oxygen isotopes, in which light and oxygen-enabled sodium alkanesulfinates catalyzed this process. This strategy was extended to the in-situ formed ketones from the photocatalytic aerobic oxidation of alkyl arenes and secondary alcohols. Furthermore, reduction of the oxygen-isotopically labeled aldehydes with NaBH4 provided the corresponding oxygen-isotopically labeled primary alcohols. We believe that the oxygen-isotopically labeling method will be widely used in chemistry, biology and medicine fields.