Cleavage Of Diols Research Articles

One‐Pot Cascade Reaction from Epoxide to Carboxylic Acids Using Bifunctional Fe‐ZSM‐5

AbstractThe quest for sustainable synthesis of carboxylic acids has led to the exploration of innovative routes and catalysts for the oxidative cleavage of carbon−carbon double bonds, prevalent in bio‐derived molecules. This process involves multiple steps including epoxidation, hydrolysis and vicinal diol cleavage, often catalysed by unsustainable homogeneous or noble‐metal catalysts. In this study, we present the utilization of Fe‐ZSM‐5 as a versatile bifunctional catalyst capable of catalysing both hydrolysis and vicinal diol cleavage steps, utilizing propylene oxide as model compound and H2O2 as oxidizing agent. The prepared Fe‐ZSM‐5 features the zeolite intrinsic Lewis and Brønsted acidity functions, essential for the hydrolysis step, as well as high fractions of monomeric FeOx species, crucial for the subsequent vicinal diol cleavage, leading to streamlined carboxylic acids formation in a one‐pot, two‐step process. Moreover, by combining Fe‐ZSM‐5 with TS‐1, renowned for its epoxidation activity, we demonstrate the complete cascade reaction in one pot, under mild conditions, starting from ethylene. Our study expands the utility of cost‐effective zeolite‐based catalysts enriched with abundant Fe metal for the one‐pot oxidative cleavage of C=C double bonds, offering a promising pathway towards sustainable carboxylic acid synthesis.

Crystal structure of (6,9-diacetyl-5,10,15,20-tetraphenylsecochlorinato)nickel(II)

Title compound 1Ni, [Ni(C46H32N4O2)], a secochlorin nickel complex, was prepared by diol cleavage of a precursor trans-dihydroxydimethylchlorin. Two crystallographically independent molecules in the structure are related by pseudo-A lattice centering, with molecules differing mainly by a rotation of one of the acetyls and an adjacent phenyl groups. The two molecules have virtually identical conformations characterized by noticeable in-plane deformation in the A1g mode and a prominent out-of-plane deformation in the B1u (ruffling) mode. Directional interactions between molecules are scarce, limited to just a few C—H...O contacts, and intermolecular interactions are mostly dispersive in nature.

Vanadium Catalyst in Micelles: Toward a Greener Aerobic Oxidative Cleavage of Vicinal Diols in Water

Aqueous micellar media offer an alternative to organic solvents for the development of safe and environmentally benign synthesis. A vanadium aminotriphenolate complex, known to be an effective catalyst for the aerobic oxidative C–C cleavage of vicinal diols in organic solvents, was incorporated in zwitterionic dodecyl phosphocholine (DPC) and in mixed TPGS-750-M:DPC micelles. It efficiently performed affording the corresponding carbonyl derivatives with no overoxidation, with catalyst loading down to 0.2 mol % and reaching TONs up to 500. The mixed micelles, which combine the enhanced stability conferred by zwitterionic DPC and the exceptional extraction properties of non-ionic TPGS-750-M, could be recycled and full conversion achieved upon reloading with catalyst and substrate. The study of the correlation between the reactivity of different substrates and their local concentration in the micellar core, derived from DOSY experiments, highlights that, while lipophilicity is important, the ease with which the substrate can access the catalyst, and therefore the location of the catalyst in the micellar phase, must also be considered when trying to rationalize reactivity in micelles.

Ionic Liquid-Supported Photocatalysts: A Reusable Environmentally Friendly Oxidation Reaction System That Uses Air and Light.

Ionic liquids are used in various fields due to their unique physical properties and are widely utilized as reaction solvents in the field of synthetic organic chemistry. We have previously proposed a new organic synthetic method in which the catalyst and reaction reagents are supported on ionic liquids. This method has various advantages, such as the ability to reuse the reaction solvent and catalyst and its facile post-reaction treatment. In this paper, we describe the synthesis of an ionic liquid-supported anthraquinone photocatalyst and the synthesis of benzoic acid derivatives using this system. This synthesis of benzoic acid derivatives via the cleavage of vicinal diols by an ionic liquid-supported anthraquinone photocatalyst is an environmentally friendly process, and furthermore, it has a simple post-reaction process, and the catalyst and solvent can both be reused. To the best of our knowledge, this is the first report on the synthesis of benzoic-acid derivatives via the cleavage of vicinal diols using light and an ionic-liquid-supported catalyst.

Structural and dimensional control of porphyrin capsules using Group 15 tris(3-pyridyl) linkers.

While supramolecular chemistry involving organic and metallo-organic host assemblies is a well-established and important field with applications in gas-storage, drug-delivery and the regio- and stereo-control of organic reactions, the use of main group elements in this setting (beyond the second row of the p-block) has been little explored. In this paper we show how periodic trends in the p-block can provide the means for systematic size and structural control in an important class of supramolecular porphyrin-based capsules. The formation of molecular and extended 2D capsule arrangements between the heavier Group 15 tris(3-pyridyl) linkers Sb(3-py)3 and Bi(3-py)3 and the metallo-porphyrins MTPP (M = Zn, Mg; TPP = tetraphenylporphyrin, 3-py = 3-pyridyl) is the first study involving heavier Group 15 pyridyl linkers. The increase in C-E bond length in the E(3-py)3 linkers moving down Group 15 (from E = P, to Sb, to Bi) can be used to alter the dimensions and structural preference of the capsules, as can oxidation of the Group 15 bridgehead atoms themselves. The subtle changes in the dimensions and Lewis acidity of the encapsulates have a dramatic effect on the rate and selectivity of the catalytic oxidative cleavage of organic diols and catalytic oxidation of α-hydroxyketones. By providing simple tools for modulating the chemical and steric properties of the capsules this work should have direct applications for the tuning of the activity and specificity of a range of catalytic systems based on main-group-based capsules of this type.

Cover Feature: Oxidative Cleavage of Vicinal Diols Catalyzed by Monomeric Fe‐Sites Inside MFI Zeolite (ChemCatChem 21/2022)

The Cover Feature shows the monomeric iron on MFI zeolite as an efficient catalyst for the oxidative cleavage of vicinal diols, while the oligomeric/bulk iron species lack activity. In their Full Paper, E. Saraçi and co-workers explore the Fe/MFI catalysts for the oxidative cleavage of ethylene glycol. Further vicinal diols, often found in biomass, where also tested. The iron species present were correlated with corresponding reaction rates revealing that monomeric Fe species inside zeolite MFI were responsible for the oxidative cleavage of C–C bonds of vicinal diols. The recyclability of the catalyst and reaction mechanism were also studied. More information can be found in the Full Paper by E. Saraçi and co-workers.

Development of a Divergent Synthetic Avenue towards Conduritol‐E, allo‐Inositol, talo‐Quercitol and Palitantin from D‐Ribose

AbstractA convenient and diverse common synthetic strategy was developed for total synthesis of conduritol‐E, allo‐inositol, talo‐quercitol, and formal synthesis of palitantin from the common polyhydroxylated cyclohexenol intermediate, which was synthesized from readily available D‐ribose. The synthetic avenue includes Barbier allylation, RCM reaction, and oxidative diol cleavage as key steps.

Oxidative Cleavage of Vicinal Diols Catalyzed by Monomeric Fe‐Sites Inside MFI Zeolite

AbstractThe oxidative cleavage of vicinal diols to carboxylic acids was investigated over heterogeneous Fe/MFI catalysts in aqueous medium, with green oxidant H2O2 and in mild reaction conditions. High conversions and selectivities (X=90 %, S=79 %) were achieved for the oxidative cleavage of ethylene glycol. Further substrates were also tested broadening the relevance of this catalyst. The employment of non‐noble and abundant Fe as the active metal and the MFI‐type zeolite as support has a clear advantage over the presently used homogeneous or noble metal‐based catalysts. A combination of complementary characterisation techniques with catalytic results is used to show that monomeric Fe species inside zeolite MFI are the active sites for the oxidative cleavage of C−C bonds of vicinal diols. The recyclability of the catalyst and reaction mechanism were also studied.

Sustainable and Selective Aerobic Oxidative C–C Bond Cleavage of Vicinal Diols under Near-Room-Temperature Condition

The selective oxidative C–C bond cleavage is essential for the production of functional molecules. Herein, a sustainable and efficient heterogeneous catalytic protocol is developed to facilitate the aerobic oxidative C–C bond cleavage, in which the selective conversion of vicinal diols to the corresponding aldehydes was achieved under a near-room-temperature condition with NH3-treated cobalt catalysts. Hydrobenzoin was selectively transformed to generate benzaldehyde with the solid ComOn/C–N catalyst, where the conversion and product selectivity reached 96.7 and 99.0% under an oxygen atmosphere, respectively. Further investigations revealed that the high catalytic activity of the catalyst is contributed to numerous oxygen defects, which lead to efficient generation of active 1O2 species. Moreover, the ComOn/C–N catalyst still exhibited a very high catalytic activity after it was continuously recycled five times. Finally, the oxidative cleavages of the C–C bond in the different 1,2-diols were also studied where more than 96.5% conversion of substrates and 99% selectivity of aldehydes were acquired under the optimal conditions.

The product-controllable aerobic oxidative cleavage of vicinal diols using vanadium-based photocatalysts

A method for the photocatalytic controllable oxidative cleavage of C–C bonds is developed with molecular oxygen as the oxidant.

Design, synthesis and cytotoxic evaluation of truncated 3′-deoxy- 3′, 3′ difluororibofuranosyl pyrimidine nucleosides

Truncated 3′-deoxy- 3′, 3′ difluororibofuranosyl pyrimidine nucleoside derivatives were synthesized from d-ribose via β-apioribo pyrimidine nucleoside intermediates 11a-c. The synthetic approach signifies that truncation at C3′ position of apioribose ring of 13a-c by oxidative cleavage of diols with Pb(OAc)4 and followed by fluorination with DAST as key steps. Cytotoxic evaluation of synthesized truncated nucleoside derivatives 16a-c and 19a-c were tested against MCF7 and MDA-MB-231 breast cancer cell lines. However, only 19a was shown minimal growth suppression activity on MDA-MB-231 cancer cell lines.

Crystal structure of 2,3-dimeth-oxy-meso-tetra-kis(penta-fluoro-phen-yl)morpholino-chlorin methyl-ene chloride 0.44-solvate.

The title morpholino-chlorin, C46H16F20N4O3, was crystallized from hexa-ne/methyl-ene chloride as its 0.44 methyl-ene chloride solvate, C46H16F20N4O3·0.44CH2Cl2. The morpholino-chlorin was synthesized by stepwise oxygen insertion into a porphyrin using a 'breaking and mending strategy': NaIO4-induced diol cleavage of the corresponding 2,3-di-hydroxy-chlorin with in situ methanol-induced, acid-catalyzed intra-molecular ring closure of the inter-mediate secochlorins bis-aldehyde. Formally, one of the pyrrolic building blocks was thus replaced by a 2,3-di-meth-oxy-morpholine moiety. Like other morpholino-chlorins, the macrocycle of the title compound adopts a ruffled conformation, and the modulation of the porphyrinic π-system chromophore induces a red-shift of its optical spectrum compared to its corresponding chlorin analog. Packing in the crystal is governed by inter-actions involving the fluorine atoms of the penta-fluoro-phenyl substituents, dominated by C-H⋯F inter-actions, and augmented by short fluorine⋯fluorine contacts, C-F⋯π inter-actions, and one severely slipped π-stacking inter-action between two penta-fluoro-phenyl rings. The solvate methyl-ene chloride mol-ecule is disordered over two independent positions around an inversion center with occupancies of two × 0.241 (5) and two × 0.199 (4), for a total site occupancy of 88%.

Bio-Based Coatings for Food Metal Packaging Inspired in Biopolyester Plant Cutin.

Metals used for food canning such as aluminum (Al), chromium-coated tin-free steel (TFS) and electrochemically tin-plated steel (ETP) were coated with a 2–3-µm-thick layer of polyaleuritate, the polyester resulting from the self-esterification of naturally-occurring 9,10,16-trihydroxyhexadecanoic (aleuritic) acid. The kinetic of the esterification was studied by FTIR spectroscopy; additionally, the catalytic activity of the surface layer of chromium oxide on TFS and, in particular, of tin oxide on ETP, was established. The texture, gloss and wettability of coatings were characterized by AFM, UV-Vis total reflectance and static water contact angle (WCA) measurements. The resistance of the coatings to solvents was also determined and related to the fraction of unreacted polyhydroxyacid. The occurrence of an oxidative diol cleavage reaction upon preparation in air induced a structural modification of the polyaleuritate layer and conferred upon it thermal stability and resistance to solvents. The promoting effect of the tin oxide layer in such an oxidative cleavage process fosters the potential of this methodology for the design of effective long-chain polyhydroxyester coatings on ETP.

Heterogeneous carbon nitride photocatalyst for C–C bond oxidative cleavage of vicinal diols in aerobic micellar medium

A visible-light promoted oxidative cleavage of vicinal diols by using CN620 as a recyclable photocatalyst in aerobic micellar medium has been developed.

Preparation of Functionalized Acylsilanes by Diol Cleavage of Cyclic 1,2‐Dihydroxysilanes

We report a study on diol cleavage of cyclic 1,2‐dihydroxysilanes for the preparation of functionalized acylsilanes. Sodium periodate turned out to be an efficient reagent for this transformation, resulting in good to excellent yields. The method is characterized by mild reaction conditions, and sometimes simple aqueous workup of the reaction mixture was sufficient to obtain the acylsilanes in high purity. An acyclic 1,2‐dihydroxysilane was readily cleaved as well.

Asymmetric total synthesis of (+)-gabosine C and (+)-4-epi-gabosine J using acetate migration and RCM reaction

A concise, unified and stereoselective total synthesis of (+)-gabosine C and (+)-4-epi-gabosine J from a common polyhydroxylated cyclohexenol intermediate which was synthesized from readily available D-ribose has been described. The synthetic avenue includes stereoselective Grignard reaction, silyl ether deprotection followed by acetate migration, RCM reaction, oxidative diol cleavage, hydroxymethylation and oxidative rearrangement as key steps.

Aerobic oxidative cleavage of 1,2-diols catalyzed by atomic-scale cobalt-based heterogeneous catalyst

The oxidative cleavage of the C–C bonds in 1,2-diols is an important transformation in synthetic organic chemistry. The challenge for this reaction is to develop a recyclable catalyst and an efficient catalytic system that operates under mild conditions. Here we report an atomically dispersed cobalt (3.8 wt% Co) on N-doped carbon catalyst, which exhibits improved catalytic activity toward the oxidative cleavage of a variety of 1,2-diols into esters, ketones or aldehydes using molecular oxygen under mild conditions. For example, the oxidative cleavage of internal diols is achieved at ambient temperature and air pressure. The robust catalyst can be reused at least seven times without regeneration treatment. The formation of highly dispersed active Co-Nx sites is demonstrated by catalyst characterization and potassium thiocyanate poisoning experiment. Mechanistic insights into monosubstituted diols indicate a sequence reaction including stepwise oxidation/nucleophilic addition/C–C bond cleavage, and reveal two reaction pathways.

Visible-light mediated C-C bond cleavage of 1,2-diols to carbonyls by cerium-photocatalysis.

We describe a photocatalytic method for the cleavage of vicinal diols to aldehydes and ketones. The reaction is catalyzed by blue light and a cerium-catalyst and the scope includes aryl as well as alkyl substituted diols. The simple protocol which works under air and at room temperature enables the valorization of abundant diols.

Chitosan: The One and Only? Aminated Cellulose as an Innovative Option for Primary Amino Groups Containing Polymers.

The aim of this study was the synthesis and in vitro characterization of aminated cellulose as alternative excipient to chitosan. The aldehyde form of cellulose was generated via the oxidative cleavage of vicinal diols by the addition of increasing concentrations of sodium periodate. The insertion of primary amines was achieved by reductive amination with ammonia. The degree of substitution was calculated via primary amino group quantification using a 2,4,6-trinitrobenzenesulfonic acid assay. Mucoadhesiveness was examined by adopting the rotating-cylinder method and tensile studies using porcine intestinal mucosa. Hydration was evaluated at pH 2-11. The successful formation of aldehydes as well as a subsequent introduction of up to 311.61 micromoles per gram of primary amines were proven to correlate with the amount of added periodate. There was a 3- to 14-fold prolongation in the mucosal residence time of the new polymer in comparison to chitosan, as measured by the rotating-cylinder method. Although cationic cellulose did not reach the maximum detachment force of chitosan, the total work of adhesion of the newly synthesized cellulose derivate was higher than that of chitosan. The higher the degree of amination, the higher the degree of hydration in neutral and alkaline aqueous media was. Compared to chitosan, the novel cationic cellulose derivative displays improved mucoadhesive properties as well as sufficient hydration at physiological pH. Therefore, aminated cellulose is a promising alternative to the cationic polymers, such as chitosan, used thus far.

Cover Picture: Efficient Vanadium‐Catalyzed Aerobic C−C Bond Oxidative Cleavage of Vicinal Diols (Adv. Synth. Catal. 17/2018)

Cover Picture: Efficient Vanadium‐Catalyzed Aerobic C−C Bond Oxidative Cleavage of Vicinal Diols (Adv. Synth. Catal. 17/2018)