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The study of a Mitsunobu reaction is an important topic. Denton and co-workers first reported a novel (2-hydroxybenzyl)diphenylphosphine oxide for realizing the catalytic Mitsunobu reaction via a five-membered phosphonium species. However, it is still worth investigating how to improve catalysts with higher efficiency. Guided by computational and experimental studies, we designed a new type of biphenyl-based phosphine oxide that would form a six-membered phosphonium species as a key intermediate to trigger the catalytic Mitsunobu reaction with a lower barrier of the rate-determining step (30.3 ​kcal/mol). DFT calculations revealed that only trans dehydration was participated in our catalytic progress and a strong π-π interaction and small spatial constraint of TS-V were crucial for high behavior. This readily accessible, highly stable, easily recyclable and efficient catalyst would boost the catalytic Mitsunobu reaction.

In order to improve the drug-likeness qualities, the antimalarial endochin-like quinolone (ELQ) scaffold has been modified by replacing the 4-(trifluoromethoxy)phenyl portion with an isoidide unit that is further adjustable by varying the distal O-substituents. As expected, the water solubilities of the new analogs are greatly improved, and the melting points are lower. However, the antimalarial potency of the new analogs is reduced to EC50 > 1 millimolar, a result ascribable to the hydrophilic nature of the new substitution. [ABSTRACT FROM AUTHOR]

The absolute stereochemical configurations of acremolides A and B were predicted by a biochemistry-based rule and unambiguously confirmed through their total syntheses. The features of the total syntheses include sequential Krische's Ir-catalyzed crotylation, Brown's borane-mediated crotylation, Mitsunobu esterification reaction, and cross-metathesis reaction. The efficient total synthesis enabled clear validation of the predicted stereochemistry for acremolides A and B. [ABSTRACT FROM AUTHOR]

The paper presents the photomechanical effect generated in new azo side-chain polyimides synthesized through a post-functionalization strategy involving the Mitsunobu reaction. Prepared azo polyimide foils were irradiated by a 405 nm diode-laser beam (intensity, I = 100 mW/cm²; polarization, Eǀǀx) for the generation of the photomechanical effect. Despite the low content of azo chromophore (substitution of the hydroxyl group was in the range of 7–35%) and thick cantilevers (thickness ~35 µm), bending angles were in the range of 30–40°. Thermal unbending was not observed for 12 months after turning off the excitation light. Our investigation showed that, despite the low content of azo chromophore, it is possible to achieve photodeformation under polarized light. To the best of our knowledge, this is the first example of the photomechanical response of azo pyridine polymers. [ABSTRACT FROM AUTHOR]

Selenosugars are gaining growing interest due to their antioxidant efficacy, and their ability to inhibit glycosidases, repair skin tissue or reduce endothelial dysfunction. Among selenosugars, those in which selenium replaces heterocyclic oxygen in a 5-membered sugar were our focus, and their coupling with phenolic compounds appears to be a strategy aimed at producing new compounds with enhanced antioxidant efficacy. In this context, the Mitsunobu reaction has been advantageously explored to obtain trans-p-coumaroyl-1,4-deoxy-2,3-O-isopropylidene-4-seleno-d-ribose, trans-caffeoyl-1,4-deoxy-2,3-O-isopropylidene-4-seleno-d-ribose, and trans-feruloyl-1,4-deoxy-2,3-O-isopropylidene-4-seleno-d-ribose. These compounds underwent removal of the iso-propylidene group, to provide the corresponding hydroxycinnamoyl-1,4-deoxy-4-seleno-d-ribose. All compounds were characterized by Nuclear Magnetic Resonance (NMR) spectroscopy and High-Resolution Mass Spectrometry (HRMS). This latter technique was pivotal for ensuing cellular metabolomics analyses. In fact, after evaluating the anti-radical efficacy through 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods, which underline the massive role of the phenolic moiety in establishing efficacy, the compounds, whose cytotoxicity was first screened in two highly oxidative-stress-sensitive cells, were tested for their wound healing properties towards human HaCaT keratinocytes cells. Caffeoyl- and feruloyl selenosugars exerted a dose-dependent repair activity, while, as highlighted by the metabolomic approach, they were poorly taken up within the cells. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) continues to be a major global health challenge and a leading cause of death from infectious diseases. Inspired by the results from a previous work by our group on antimycobacterial N-alkylnitrobenzamides, which are structurally related to the nitrobenzamide family of decaprenylphosphoryl-β-d-ribose oxidase (DprE1) inhibitors, the present study explored a broad array of substituted benzamides. We particularly focused on previously unexplored 3,5-dinitrobenzamide derivatives. Starting with 3,5-dinitrobenzoic acid, we synthesized a diverse library of amides, incorporating both linear and cyclic amine moieties and also assessed the impact of terminal aromatic groups connected through ether, ester, or amide bonds on the bioactivity of the compounds. The synthesis primarily utilized nucleophilic addition/elimination, SN2, and Mitsunobu reactions. The activity was impacted mainly by two structural features, the addition of an aromatic moiety as a terminal group and the type of linker. The most interesting compounds (c2, d1, and d2, MIC = 0.031 μg/mL) exhibited activities against Mycobacterium Tuberculosis (Mtb) H37Rv comparable to isoniazid. Complementary computational studies helped elucidate potential interactions with DprE1, enhancing our understanding of the molecular basis of their action. Our findings suggest that the most active compounds provide a promising foundation for the continued development of new antimycobacterial agents. [ABSTRACT FROM AUTHOR]

Silybin is a natural compound extensively studied for its hepatoprotective, neuroprotective and anticancer properties. Envisioning the enhancement of silybin potential by suitable modifications in its chemical structure, here, a series of new 7-O-alkyl silybins derivatives were synthesized by the Mitsunobu reaction starting from the silybins and tyrosol-based phenols, such as tyrosol (TYR, 3), 3-methoxytyrosol (MTYR, 4), and 3-hydroxytyrosol (HTYR, 5). This research sought to explore the antioxidant and anticancer properties of eighteen new derivatives and their mechanisms. In particular, the antioxidant properties of new derivatives outlined by the DPPH assay showed a very pronounced activity depending on the tyrosyl moiety (HTYR > MTYR >> TYR). A significant contribution of the HTYR moiety was observed for silybins and 2,3-dehydro-silybin-based derivatives. According to the very potent antioxidant activity, 2,3-dehydro-silybin derivatives 15ab, 15a, and 15b exerted the most potent anticancer activity in human prostate cancer PC-3 cells. Furthermore, flow cytometric analysis for cell cycle and apoptosis revealed that 15ab, 15a, and 15b induce strong G1 phase arrest and increase late apoptotic population in PC-3 cells. Additionally, Western blotting for apoptotic marker cleaved caspase-3 confirmed apoptosis induction by these silybin derivatives in PC-3 cells. These findings hold significant importance in the investigation of anticancer properties of silybin derivatives and strongly encourage swift investigation in pre-clinical models and clinical trials. [ABSTRACT FROM AUTHOR]

In order to improve the drug-likeness qualities, the antimalarial endochin-like quinolone (ELQ) scaffold has been modified by replacing the 4-(trifluoromethoxy)phenyl portion with an isoidide unit that is further adjustable by varying the distal O-substituents. As expected, the water solubilities of the new analogs are greatly improved, and the melting points are lower. However, the antimalarial potency of the new analogs is reduced to EC50 > 1 millimolar, a result ascribable to the hydrophilic nature of the new substitution.

A simple and rapid access to fluorinated dithioesters was developed by a one-pot sequence corresponding to a Grignard reaction—Mitsunobu type substitution. These activated dithioesters have shown excellent reactivity in an aminolysis reaction from simple or more complex primary amines such as cinchona alkaloids. A stoichiometric amount of amine was sufficient to prepare various thioamides, including a 4-styrenylthioamide cinchonidine monomer, under environmentally friendly conditions, at room temperature, and in a very short time. [ABSTRACT FROM AUTHOR]

(5R)-Cleistenolide and a few related analogues have been synthesized starting from d-glucose. The key steps of the synthesis included a Z-selective Wittig olefination and an intramolecular Mitsunobu reaction with an inversion of configuration at the C-5 position. In vitro antiproliferative activity of synthesized compounds was tested on a panel of eight human tumour cells and against a single normal cell line (MRC-5). The majority of tested compounds showed strong antiproliferative effects on certain human tumour cells and all of them showed negligible toxicity to normal foetal lung fibroblasts (MRC-5). The most active compound obtained in this work is lactone 5, which in MDA--MB 231 cell culture showed the same activity as doxorubicin (IC50 0.09 μM). Strong antiproliferative activities of analogues 2, 5 and 6 were recorded in the K562 cell line (IC50 0.21, 0.34 and 0.33 μM, respectively), in which they showed very similar activities to doxorubicin (IC50 0.25 μM). A performed SAR study revealed that a change in the stereochemistry at the C-5 position may increase the activity of resulting stereoisomers. [ABSTRACT FROM AUTHOR]

Derivatives of cinnamic acid have several pharmacological actions, such as antimicrobial activity. Therefore, in the present study, a series of fourteen alkyl and aryl derivatives from (E)-2-nitrocinnamic acid were obtained using Fischer esterification, nucleophilic substitution with halides, and Mitsunobu reaction. Esters were evaluated for antifungal activity against several strains of Candida spp. using nystatin as a positive control. Among the synthetic derivatives obtained, nine are compounds unprecedented in the literature. The characterization of chemical structures was carried out using the techniques of IR, 1H-NMR and 13C-NMR spectroscopy, and high-resolution mass spectrometry. Isopropyl 2-nitrocinnamate (4) was the compound that showed the best antifungal activity (MIC = 513.52 μM) against all fungal strains, followed by compound perillyl 2-nitrocinnamate (14) with MIC = 390.99–781.98 μM. [ABSTRACT FROM AUTHOR]

Silybin is a natural compound extensively studied for its hepatoprotective, neuroprotective and anticancer properties. Envisioning the enhancement of silybin potential by suitable modifications in its chemical structure, here, a series of new 7-O-alkyl silybins derivatives were synthesized by the Mitsunobu reaction starting from the silybins and tyrosol-based phenols, such as tyrosol (TYR, 3), 3-methoxytyrosol (MTYR, 4), and 3-hydroxytyrosol (HTYR, 5). This research sought to explore the antioxidant and anticancer properties of eighteen new derivatives and their mechanisms. In particular, the antioxidant properties of new derivatives outlined by the DPPH assay showed a very pronounced activity depending on the tyrosyl moiety (HTYR > MTYR >> TYR). A significant contribution of the HTYR moiety was observed for silybins and 2,3-dehydro-silybin-based derivatives. According to the very potent antioxidant activity, 2,3-dehydro-silybin derivatives 15ab, 15a, and 15b exerted the most potent anticancer activity in human prostate cancer PC-3 cells. Furthermore, flow cytometric analysis for cell cycle and apoptosis revealed that 15ab, 15a, and 15b induce strong G1 phase arrest and increase late apoptotic population in PC-3 cells. Additionally, Western blotting for apoptotic marker cleaved caspase-3 confirmed apoptosis induction by these silybin derivatives in PC-3 cells. These findings hold significant importance in the investigation of anticancer properties of silybin derivatives and strongly encourage swift investigation in pre-clinical models and clinical trials.

Intravascular thrombus formation is one of the main causes of such deadly diseases and pathologies as ischemic heart disease, ischemic stroke, pulmonary embolism, atrial fibrillation, and venous thromboembolism [1, 2]. That is why the development of new approaches for preventing intravascular blood coagulation is an important task for biochemistry and biotechnology. Most of biomolecules that target clotting factors. However, in our study we focused on another type of molecules, which are direct inhibitors of fibrin polymerization. As a scaffold, we have used a calix[4]arene molecule because of its tunable diversity at both upper and lower rims, its pre-organized nonpolar cavities, pre-organized ion-bonding sites and well-defined conformations [3]. Previously we have shown that calix[4]arenes are active inhibitors of fibrin polymerization process. Binding to the ‘A’-knob of fibrin desAB molecule calix[4] arenes prevents knob-hole interactions between different fibrin molecules thus suppressing clotting. Recent studies proved the efficacy of sodium salt of 5, 11, 17, 23-bis(dihydroxyphos phoryl)methylcalix[4]arene (C-145) as an effective anticoagulant agent [4, 5]. Molecular dynamic studies of C-145 demonstrated the importance of conformation of the macrocycle for its fibrin-binding activity. In particular calyx[4]arene has two different conformations of its cup (the macrocycle) that can be described as ‘1,3-alternate’ (opened) or ‘conus-conformation’ (fixed). Aim. The purpose of the present study was to develop a method for the fixation of ‘fixed’ conformation for estimation of the impact of calix[4]arene structure on the efficacy of its anticoagulant activity. This was achieved by substitution of the lower rim of C-145 analogue. Metods. Calix[4]arene C-145 was obtained according to the method described in [6] with one additional step that included Mitsunobu reaction in order to obtain disubstituted calixarene C-145F (Fig. 1). Modeling of 3D-structure of calix[4]arene C-145 and its analogue C-145F was performed in Maestro, Schrodinger software. Calix[4]arene C-145F (compound 6) was obtained in 4 steps starting with Duff reaction. Calix[4]arene methylene-bis-phosphonic ester 3 was prepared via addition of diisopropylphosphite in presence of metallic sodium to the parent calix[4]arene aldehyde 2. Further steps included Mitsunobu reaction, that afforded dipropoxycalix[4]arene 5 with rather good yields (80%), following the hydrolysis step that resulted in compound 6 in almost quantitative yield. Results. Using a 2D NMR-NOESY spectroscopy, we can observe a distinct cross-peak between an aromatic singlet with a chemical shift on 7.72 ppm and protons of isopropyl group with a chemical shift on 1.62 ppm, which are moved in the strong field (Fig. 2). This correlation proves us their steric proximity, that can be observed only in conus-conformation (Fig. 3, A), not in the 1,3-alternate. So, in this work we confirmed that disubstituted calix[4]arenes (low-rim modification) have fixed conus conformation. NMR spectroscopy proves us that calix[4]arene C145F exists in fixed conus-conformation. Discussion. Presented experiment represents how easily we can modify calix[4]arene cup in order to obtain molecule with new chemical and physical properties. The fine-tuning and incorporation of different ligating sites in the calix[4]arene scaffold may be used to produce numerous molecules, forming a library of compounds. Comparison of the action of fibrin polymerization of calix[4]arene molecules with fixed and opened conformations will allow to estimate the role of different conformation in fibrin recognition and will support targeted design of even more effective calix[4]arene-based inhibitors of blood clotting in future. Conclusions. The easy method of the fixation of conus conformation of calix[4]arene cup will be useful for synthesis of novel functionally active compounds. We believe that further development and study of different calix[4]arenes will help scientists to obtain bioactive molecules that could be prospective anti-thrombotic drugs. [ABSTRACT FROM AUTHOR]

A small library of 6-O-sucrose monoester surfactants has been synthesized and tested against various microorganisms. The synthetic procedure involved a modified Mitsunobu reaction, which showed improved results compared to those present in the literature (higher yields and larger scope). The antifungal activities of most of these glycolipids were satisfactory. In particular, sucrose palmitoleate (URB1537) showed good activity against Candida albicans ATCC 10231, Fusarium spp., and Aspergillus fumigatus IDRAH01 (MIC value: 16, 32, 64 µg/mL, respectively), and was further characterized through radical scavenging, anti-inflammatory, and biocompatibility tests. URB1537 has been shown to control the inflammatory response and to have a safe profile. [ABSTRACT FROM AUTHOR]

The 3C-like protease (also known as Mpro) plays a key role in SARS-CoV-2 replication and has similar substrates across mutant coronaviruses, making it an ideal drug target. We synthesized 19 thiazolidinedione derivatives via the Knoevenagel condensations and Mitsunobu reactions as potential 3C-like protease inhibitors. The activity of these inhibitors is screened in vitro by employing the enzymatic screening model of 3C-like protease using fluorescence resonance energy transfer. Dithiothreitol is included in the enzymatic reaction system to avoid non-specific enzymatic inhibition. Active inhibitors with diverse activity are found in this series of compounds, and two representative inhibitors with potent inhibitory activity are highlighted. [ABSTRACT FROM AUTHOR]

Stereoselective synthesis has been emerging as a resourceful tool because it enables the obtaining of compounds with biological interest and high enantiomeric purity. Flavonoids are natural products with several biological activities. Owing to their biological potential and aiming to achieve enantiomerically pure forms, several methodologies of stereoselective synthesis have been implemented. Those approaches encompass stereoselective chalcone epoxidation, Sharpless asymmetric dihydroxylation, Mitsunobu reaction, and the cycloaddition of 1,4-benzoquinone. Chiral auxiliaries, organo-, organometallic, and biocatalysis, as well as the chiral pool approach were also employed with the goal of obtaining chiral bioactive flavonoids with a high enantiomeric ratio. Additionally, the employment of the Diels–Alder reaction based on the stereodivergent reaction on a racemic mixture strategy or using catalyst complexes to synthesise pure enantiomers of flavonoids was reported. Furthermore, biomimetic pathways displayed another approach as illustrated by the asymmetric coupling of 2-hydroxychalcones driven by visible light. Recently, an asymmetric transfer hydrogen-dynamic kinetic resolution was also applied to synthesise (R,R)-cis-alcohols which, in turn, would be used as building blocks for the stereoselective synthesis of flavonoids. [ABSTRACT FROM AUTHOR]

A simple and rapid access to fluorinated dithioesters was developed by a one-pot sequence corresponding to a Grignard reaction—Mitsunobu type substitution. These activated dithioesters have shown excellent reactivity in an aminolysis reaction from simple or more complex primary amines such as cinchona alkaloids. A stoichiometric amount of amine was sufficient to prepare various thioamides, including a 4-styrenylthioamide cinchonidine monomer, under environmentally friendly conditions, at room temperature, and in a very short time.

(R)-Tenofovir phenyl ester ((R)-1) and (R)-tenofovir diphenyl ester ((R)-2) are key intermediates for the practical synthesis of tenofovir alafenamide fumarate, which is a mainstay antiretroviral for the treatment of chronic hepatitis B and HIV-1 infections. This article deals with the chiral analysis of (R)-1 and (R)-2 against their respective optical impurity (S)-tenofovir phenyl ester ((S)-1) and (S)-tenofovir diphenyl ester ((S)-2) using a polysaccharide-coated chiral stationary phase (CSP) by normal-phase high-performance liquid chromatography (HPLC). To this end, a chiral synthetic strategy for (S)-2 was efficiently executed capitalizing on a classical Mitsunobu reaction to stereospecifically invert the configuration of chiral carbon in readily accessible (R)-HPA ((R)-4) to deliver (S)-HPA ((S)-4), from which (S)--tenofovir ((S)-3) was in turn prepared and further transformed into (S)-2. With reference substance (S)-2 in hand, a chiral analytical method for (R)-2 using Chiralpak AD-H as CSP by normal-phase HPLC has been developed and validated. The validation results indicated that this chiral analytical method has been achieved with satisfactory separation effect, high sensitivity, and good precision and accuracy, and thus can be deployed for the determination of optical impurities in samples of (R)-1 (via derivation to (R)-2) and (R)-2.

Natural and synthetic coumarins are often considered privileged scaffolds for obtaining pharmacological agents with hypoglycemic activity. Chemical modification of coumarins often leads to antidiabetic agents with greater efficacy. In the present work, twenty monoterpene-substituted 7-hydroxycoumarins were synthesized. A new approach using the Mitsunobu reaction was shown to be effective for the synthesis of target compounds. All of the synthesized compounds were evaluated in an oral glucose tolerance test, and two of them containing geranyl and (-)-myrtenyl substituents showed in vivo hypoglycemic action. A possible mechanism of action of these compounds may include inhibition of DPP IV, which was proved in an in vitro test. [ABSTRACT FROM AUTHOR]

The Mitsunobu reaction plays a vital part in organic chemistry due to its wide synthetic applications. It is considered as a significant reaction for the interconversion of one functional group (alcohol) to another (ester) in the presence of oxidizing agents (azodicarboxylates) and reducing agents (phosphines). It is a renowned stereoselective reaction which inverts the stereochemical configuration of end products. One of the most important applications of the Mitsunobu reaction is its role in the synthesis of natural products. This review article will focus on the contribution of the Mitsunobu reaction towards the total synthesis of natural products, highlighting their biological potential during recent years. [ABSTRACT FROM AUTHOR]

In the present study, we continue our work related to the synthesis of 1,8-naphthalimide and carborane conjugates and the investigation of their anticancer activity and DNA-binding ability. For this purpose, a series of 4-carboranyl-1,8-naphthalimide derivatives, mitonafide, and pinafide analogs were synthesized using click chemistry, reductive amination, amidation, and Mitsunobu reactions. The calf thymus DNA (ct-DNA)-binding properties of the synthesized compounds were investigated by circular dichroism (CD), UV–vis spectroscopy, and thermal denaturation experiments. Conjugates 54–61 interacted very strongly with ct-DNA (∆Tm = 7.67–12.33 °C), suggesting their intercalation with DNA. They were also investigated for their in vitro effects on cytotoxicity, cell migration, cell death, cell cycle, and production of reactive oxygen species (ROS) in a HepG2 cancer cell line as well as inhibition of topoisomerase IIα activity (Topo II). The cytotoxicity of these eight conjugates was in the range of 3.12–30.87 µM, with the lowest IC50 value determined for compound 57. The analyses showed that most of the conjugates could induce cell cycle arrest in the G0/G1 phase, inhibit cell migration, and promote apoptosis. Two conjugates, namely 60 and 61, induced ROS production, which was proven by the increased level of 2′-deoxy-8-oxoguanosine in DNA. They were specifically located in lysosomes, and because of their excellent fluorescent properties, they could be easily detected within the cells. They were also found to be weak Topo II inhibitors. [ABSTRACT FROM AUTHOR]

Four stereoisomeric monoether derivatives, based on axially chiral (R)- or (S)-BINOL bearing a chiral (+)- or (−)-neomenthyloxy group were synthesised and fully characterised by NMR spectroscopy and X-ray crystallography. The respective tris-monophosphites were thereof prepared and fully characterised. The coordination ability of the new bulky phosphites with Rh(CO)2(acac), was attested by 31P NMR, which presented a doublet in the range of δ = 120 ppm, with a 1J(103Rh-31P) coupling constant of 290 Hz. The new tris-binaphthyl phosphite ligands were further characterised by DFT computational methods, which allowed us to calculate an electronic (CEP) parameter of 2083.2 cm−1 and an extremely large cone angle of 345°, decreasing to 265° upon coordination with a metal atom. Furthermore, the monophosphites were applied as ligands in rhodium-catalysed hydroformylation of styrene, leading to complete conversions in 4 h, 100% chemoselectivity for aldehydes and up to 98% iso-regioselectivity. The Rh(I)/phosphite catalytic system was also highly active and selective in the hydroformylation of disubstituted olefins, including (E)-prop-1-en-1-ylbenzene and prop-1-en-2-ylbenzene. [ABSTRACT FROM AUTHOR]

It was recently reported that a (2-hydroxybenzyl)phosphine oxide (2-HOBPO) can serve as a phosphorus-centered catalyst for the stereo-invertive coupling of aliphatic alcohols and acidic pronucleophiles (akin to a Mitsunobu reaction, but without additional reagents). Herein, we report an improved synthesis, which provides direct access to systematically varied 2-HOBPOs in a single step from commercially available precursors (salicylaldehydes and secondary phosphines). The efficiency and generality of the synthetic method enabled limited structure–activity relationship (SAR) studies, from which it was determined that substituents on both the phenolic and phosphine oxide portions can exert significant influence on the turnover frequency (TOF) of each catalyst. Importantly, for all catalytically active 2-HOBPOs examined, the molecularity of catalyst in the rate law of the alcohol coupling was determined to be <1. Thus, for high catalyst loadings, differences in catalytic activity between 2-HOBPOs appear to be dominated by differences in catalytic auto-inhibition, while for low catalyst loadings, differences are attributed to inherent differences in the energetic span of the catalytic cycle, ignoring off-cycle species, in good agreement with density functional theory (DFT) modeling at the ωB97X-D/6-311G(d,p) level. [ABSTRACT FROM AUTHOR]

Routes are reported for the synthesis of both (1 R)- and (1 S)- tert -butyl-(4-oxocyclopent-2-en-1-yl)carbamate 2. Featuring Mitsunobu reactions with di- tert -butyl iminodicarbonate, both syntheses begin from (S)-4-[(tert -butyldimethylsilyl)oxy]cyclopent-2-en-1-one (3) and take advantage of the 1,4-cyclopentenyl dioxygenation pattern of this optically active starting material. Thus both (−)- and (+)- 2 have been accessed from 3 in an enantiodivergent manner in 11% and 10% overall yield over five and seven reaction steps, respectively. [ABSTRACT FROM AUTHOR]

All possible stereoisomers of cis- and trans-2-fluorocyclopentan-1-ols were obtained by kinetically controlled deracemization in the presence of lipases in organic media. High enantioselectivities and good yields of stereomers were obtained for all substrates. Optically pure 1,2-fluorocyclopentan-1-ols were converted to 2- fluoro-cyclopentan-1-amines using the Mitsunobu reaction. The absolute configurations were determined using the Kazlauskas rule and chemical correlation. The interaction of substrates with enzymes has considered using Koshland induced fit theory. [ABSTRACT FROM AUTHOR]

An efficient total synthesis of the naturally occurring anti-inflammatory and antitumour 8-O-4′-neolignans, surinamensinols A and B, has been accomplished from commercially available allyl alcohol and (S)-ethyl lactate. The synthetic sequence involves a palladium-catalysed Suzuki–Miyaura cross-coupling reaction followed by a chiral Mitsunobu­ reaction as the key steps. This is the first report of the simultaneous stereoselective total synthesis of surinamensinols A and B through a single approach involving only six steps.

Abstract Two series of N-methyliminodiacetic acid (MIDA) boronates were prepared and their mesomorphic properties were investigated. MIDA-substituted benzoic acid esters were synthesized via the Mitsunobu reaction. The second series of MIDA benzyl ether derivatives was prepared via Williamson etherification and subsequent borylation. Both series exhibit smectic A (SmA) phases. In the case of MIDA boronate esters, a substitution with perfluorinated side chains led to increased transition temperatures and broadening of the SmA phases. The phase geometries of the mesophases were determined by X-ray diffraction. Quantum-chemical calculations provided further insight into the packing model.

Tetrahydropyrenophorol, an interesting macrodiolide, was isolated from the plant Fagonia cretica. The total synthesis of (–)-1-tetrahydropyrenophorol was achieved in an elegant and linear manner from readily an accessible racemic epoxide. The archetypal reactions include regioselective opening of the epoxide, Sharpless asymmetric dihydroxylation, and Mitsunobu cyclodimerization to construct the requisite 16-membered bis-lactone. The synthetic approach demonstrated here is very simple and could be used for the syntheses of related compounds in an economic and highly stereoselective way.

In the current research on 13C-labeled compounds breath test of liver function, methacetin-methoxy-13C is the most potential substrate. To study a new method for synthesis methacetin-methoxy-13C, methanol-13C was used as the labeled material, methacetin-methoxy-13C was synthesized efficiently through Mitsunobu reaction and functional group modification. The synthesis yield was 63% and the chemical purity was above 99%. At the same time, this method was used to synthesize 4-methoxybenzoic acid-methoxy-13C with methanol-13C as the labeled material. The synthesis yield was 67% and the chemical purity was above 99%. The new scheme for the synthesis of methacetin-methoxy-13C with Mitsunobu reaction as the key reaction could provide a basis for the study of liver function by breath test.

The Mitsunobu reaction plays a vital part in organic chemistry due to its wide synthetic applications. It is considered as a significant reaction for the interconversion of one functional group (alcohol) to another (ester) in the presence of oxidizing agents (azodicarboxylates) and reducing agents (phosphines). It is a renowned stereoselective reaction which inverts the stereochemical configuration of end products. One of the most important applications of the Mitsunobu reaction is its role in the synthesis of natural products. This review article will focus on the contribution of the Mitsunobu reaction towards the total synthesis of natural products, highlighting their biological potential during recent years.

The article presents a study of the effectiveness of Transformer Neural Networks (TNN) in the unsupervised learning of organic chemical reactions. Topics discussed include the significance of the model to downstream applications requiring atom-mapping and chemical reaction rules, benefit of using symbolic representations and the means to autonomously learn from chemical data, and the role of the attention matrix construction for a selected layer and head in the attention-guided algorithm.

A convergent approach for the synthesis of the two key fragments (C1-C4 and C5-C14) of cytospolide D is described. Key transformations include MacMillan's crossed aldol, Sharpless asymmetric dihydroxylation (AD) and Mitsunobu inversion reactions. [ABSTRACT FROM AUTHOR]

The coupling of a nucleobase is a key step in the synthesis of most nucleoside analogs, e.g. carbocyclic nucleosides, isonucleosides and acyclic nucleosides. The synthetic strategies for nucleosides based on Nglycosylation are not applied when the nucleobase is not linked to the anomeric center. Thus, other methods have been employed, mainly those based on the alkylation of nucleobases. The Mitsunobu reaction, in which a hydroxy group is replaced by a nucleophile, has also been extensively applied, generating a diversity of molecules, including pharmaceuticals and their precursors. In this review the usefulness of this reaction for the coupling of nucleobases to non-anomeric positions of sugars, carbasugars and other homocyclic and linear structures is highlighted and discussed, covering purines and pyrimidines as pronucleophiles. [ABSTRACT FROM AUTHOR]

Mitsunobu reactions of cannabidiol (CBD) as the acid component and primary alcohols, for example benzyl, allyl, propargyl and methyl glycolate as the alcohol component gave the corresponding bis-alkylated CBD derivatives which were also obtained by alkylating CBD with the corresponding alkyl bromides. Alkylation of CBD with methyl bromoacetate followed by saponification of the two ester moieties and neutralization of the di-carboxylic acid afforded a water-soluble CBD bis-acetate bis-potassium salt. [ABSTRACT FROM AUTHOR]

It was recently reported that a (2-hydroxybenzyl)phosphine oxide (2-HOBPO) can serve as a phosphorus-centered catalyst for the stereo-invertive coupling of aliphatic alcohols and acidic pronucleophiles (akin to a Mitsunobu reaction, but without additional reagents). Herein, we report an improved synthesis, which provides direct access to systematically varied 2-HOBPOs in a single step from commercially available precursors (salicylaldehydes and secondary phosphines). The efficiency and generality of the synthetic method enabled limited structure–activity relationship (SAR) studies, from which it was determined that substituents on both the phenolic and phosphine oxide portions can exert significant influence on the turnover frequency (TOF) of each catalyst. Importantly, for all catalytically active 2-HOBPOs examined, the molecularity of catalyst in the rate law of the alcohol coupling was determined to be

Four stereoisomeric monoether derivatives, based on axially chiral (R)- or (S)-BINOL bearing a chiral (+)- or (−)-neomenthyloxy group were synthesised and fully characterised by NMR spectroscopy and X-ray crystallography. The respective tris-monophosphites were thereof prepared and fully characterised. The coordination ability of the new bulky phosphites with Rh(CO)2(acac), was attested by 31P NMR, which presented a doublet in the range of δ = 120 ppm, with a 1J(103Rh-31P) coupling constant of 290 Hz. The new tris-binaphthyl phosphite ligands were further characterised by DFT computational methods, which allowed us to calculate an electronic (CEP) parameter of 2083.2 cm−1 and an extremely large cone angle of 345°, decreasing to 265° upon coordination with a metal atom. Furthermore, the monophosphites were applied as ligands in rhodium-catalysed hydroformylation of styrene, leading to complete conversions in 4 h, 100% chemoselectivity for aldehydes and up to 98% iso-regioselectivity. The Rh(I)/phosphite catalytic system was also highly active and selective in the hydroformylation of disubstituted olefins, including (E)-prop-1-en-1-ylbenzene and prop-1-en-2-ylbenzene.

The Mitsunobu reaction basically consists in the conversion of an alcohol into an ester under inversion of configuration, employing a carboxylic acid and a pair of two auxiliary reagents, mostly triphenylphosphine and a dialkyl azodicarboxylate. This reaction has been frequently used in carbohydrate chemistry for the modification of sugar hydroxy groups. Modification at the anomeric position, leading mainly to anomeric esters or glycosides, is of particular importance in the glycosciences. Therefore, this review focuses on the use of the Mitsunobu reaction for modifications of sugar hemiacetals. Strikingly, unprotected sugars can often be converted regioselectively at the anomeric center, whereas in other cases, the other hydroxy groups in reducing sugars have to be protected to achieve good results in the Mitsunobu procedure. We have reviewed on the one hand the literature on anomeric esterification, including glycosyl phosphates, and on the other hand glycoside synthesis, including S- and N-glycosides. The mechanistic details of the Mitsunobu reaction are discussed as well as this is important to explain and predict the stereoselectivity of anomeric modifications under Mitsunobu conditions. Though the Mitsunobu reaction is often not the first choice for the anomeric modification of carbohydrates, this review shows the high value of the reaction in many different circumstances.

N′-Alkyl hydrazides were effectively synthesized by routes featuring installation, alkylation, and removal of a trifluoroacetyl group. A set of amino acid derived hydrazides were acylated using trifluoroacetic anhydride, and the resulting trifluoroacetyl hydrazides were alkylated with alcohols in Mitsunobu reactions and with alkyl halides under alkaline conditions. Removal of the trifluoroacetyl group was affected under reductive and hydrolytic conditions to provide the respective N′-alkyl hydrazides. This three-step process may be performed without isolation of intermediates to yield N′-alkyl hydrazide after a single chromatographic purification. [ABSTRACT FROM AUTHOR]

The article discusses a study on a two-step route, which is Mitsunobu followed by Schiff base reactions, to asymmetrically substituted pyridazinones from maleic hydrazide with 2-, 3-, or 4-pyridinecarboxaldehyde. Highlights include the reaction of maleic hydrazide with ethanolamine under Mitsunobu conditions, the use of ethanolamine when performing the Mitsunobu step, and hydrogen bonded dimers and close stacking of pyridazinone moieties.

For over half a century, thousands of tons of triphenylphosphine oxide Ph3P(O) have been produced every year from the chemical industries as a useless chemical waste. Here we disclose efficient transformations of Ph3P(O) with cheap resource-abundant metallic sodium finely dispersed in paraffin oil. Ph3P(O) can be easily and selectively transformed to three reactive organophosphorus intermediates—sodium diphenylphosphinite, sodium 5H-benzo[b]phosphindol-5-olate and sodium benzo[b]phosphindol-5-ide—that efficiently give the corresponding functional organophosphorus compounds in good yields. These functional organophosphorus compounds are difficult to prepare but highly industrially useful compounds. This may allow Ph3P(O) to be used as a precious starting material for highly valuable phosphorus compounds. As a byproduct of organic syntheses including the Wittig, Staudinger, and Mitsunobu reactions, triphenylphosphine oxide is often not recycled. Here a transformation of the waste product with metallic sodium to three organophosphorous compounds is presented. [ABSTRACT FROM AUTHOR]

In this study, as a result of azo coupling of diazonium salts prepared with various aromatic amines with 2-(4-methylphenyl)-1H-indole and 2-(4-chlorophenyl)-1H-indole compounds, a series of new hetarylazo indole dyes were synthesized. N-substituted indole derivatives were synthesized by alkylation of the prepared dyes with the isopropyl alcohol from the N-position by Mitsunobu reaction. The chemical structures of the synthesized compounds were determined by NMR, FT-IR, UV-vis, mass spectrometry and elemental analysis. In order to determine the photophysical properties of the dyes obtained, visible region absorption spectra were examined in solvents of different polarity. In addition, the behavior of acid and base addition on absorption maxima were examined in detail. [ABSTRACT FROM AUTHOR]

A simple and efficient route for the synthesis of new glycoconjugates has been developed. The approach acts as a model for a mini-library of compounds with a deoxy-selenosugar core joined to a polyphenolic moiety with well-known antioxidant properties. An unexpected stereocontrol detected in the Mitsunobu key reaction led to the most attractive product showing a natural d-configuration. Thus, we were able to obtain the target molecules from the commercially available d-ribose via a shorter and convenient sequence of reactions.

• First example of glycopolymers containing five-membered iminosugars. • Robust synthesis of biocompatible azide-functionalized polymethacrylates. • Anchoring of iminosugars to functionalized copolymers by click chemistry. Iminosugars are carbohydrate mimetics that constitute the main group of oligosaccharide processing enzyme inhibitors. They play an important role in cell-cell recognition processes, thereby presenting a wide range of potential therapeutic applications. In this work, we present the first examples of glycopolymers containing five-membered iminosugars. The preparation is carried out by constructing first a biocompatible water-soluble and pH-responsive 2-hydroxyethyl methacrylate (HEMA)-based copolymer by RAFT polymerization with an excellent control on the copolymer composition and low polydispersity (M n = 19,800; M w = 23,800; M w /M n = 1.2; experimental copolymer mole composition (by 1H NMR): pHEMA 49% - co -pDMAEMA 51%). One-pot azidation of its primary hydroxyl groups by Mitsunobu reaction led to a full functionalization of the HEMA residues. Subsequently, a selection of alkynyl pyrrolidine iminosugars showing glycosidase inhibition properties, were anchored to the functionalized azido-polymer through CuAAC click reaction furnishing successfully the aimed water-soluble glycopolymers, which were then subjected to biological evaluation as enzyme inhibitors. [ABSTRACT FROM AUTHOR]

Starting from a chiral secondary alcohol, novel enantiopure 1,4-aminoalkylphenols (AAPs) were prepared by exploiting conventional organic transformations such as the Mitsunobu reaction, Eschweiler-Clarke N -methylation, and demethylation of anisoles. The catalytic activity of the 1,4-AAPs was investigated in enantioselective Et2Zn addition to benzaldehyde. They were found to accelerate the Et2Zn addition to benzaldehyde. High yields and enantioselectivities (e.g., 95% yield and 82% ee) were achieved. [ABSTRACT FROM AUTHOR]

In this report, we describe the synthetic elaboration of the easily available enantiomerically pure β-amino alcohols. Attempted direct substitution of the hydroxyl group by azido-functionality in the Mitsunobu reaction with hydrazoic acid was inefficient or led to a diastereomeric mixture. These outcomes resulted from the participation of aziridines. Intentionally performed internal Mitsunobu reaction of β-amino alcohols gave eight chiral aziridines in 45−82% yield. The structural and configuration identity of products was confirmed by NMR data compared to the DFT calculated GIAO values. For 1,2,3-trisubstituted aziridines slow configurational inversion at the endocyclic nitrogen atom was observed by NMR at room temperature. Moreover, when aziridine was titrated with Zn(OAc)2 under NMR control, only one of two N-epimers directly participated in complexation. The aziridines underwent ring opening with HN3 to form the corresponding azido amines as single regio- and diastereomers in 90−97% yield. Different results were obtained for 1,2-disubstituted and 1,2,3-trisubstituted aziridines. For the later aziridines ring closure and ring opening occurred at different carbon stereocenters, thus yielding products with two inverted configurations, compared to the starting amino alcohol. The 1,2-disubstituted aziridines produced azido amines of the same configuration as the starting β-amino alcohols. To obtain a complete series of diastereomeric vic-diamines, we converted the amino alcohols into cyclic sulfamidates, which reacted with sodium azide in SN2 reaction (25−58% overall yield). The azides obtained either way underwent the Staudinger reduction, giving a series of six new chiral vic-diamines of defined stereochemistries.

Two mild and efficient strategies have been developed for the O-functionalisation of 4-hydroxy-6-alkyl-2-pyrones, by using them as nucleophilic partners in oxa-Michael additions and the Mitsunobu reaction. The reactions proceed in moderate to excellent yields on a range of substrates containing useful functionality. The reactions serve as practical and valuable synthetic methods to construct complex 2-pyronyl ethers, which are found embedded in a number of natural products.