Ether Moiety Research Articles

A Universal Support for the Solid-Phase Synthesis of Peptidyl-tRNA Mimics.

Hydrolysis-resistant RNA-peptide conjugates that mimic peptidyl-tRNAs are often required for structural and functional studies of protein synthesis at the ribosome. These conjugates can be synthesized by solid-phase chemical synthesis, which allows maximum flexibility in both the peptide and RNA sequence. The commonly used strategy is based on (3'-N-aminoacyl)-3'-amino-3'-deoxyadenosine solid supports, which already contain the first C-terminal amino acid of the target peptidyl chain. This is a limitation in the sense that different individual supports must be synthesized for different C-terminal amino acids. In this study, we demonstrate a solution to this problem by introducing a novel universal support. The key is a free ribose 3'-NH2 group that can be coupled to any amino acid. This is made possible by a photocleavable ether moiety that links the ribose 2'-O to the support, thus avoiding the typical O-to-N migration that occurs when using 2'-O-acyl linked solid supports. Once assembled, the conjugate is readily cleaved by UV irradiation. The structural integrity of the obtained peptidyl-RNA conjugates was verified by mass spectrometry analysis. In conclusion, the new photocleavable solid support makes the synthesis of 3'-peptidyl tRNA mimics of different peptidyl chains significantly more efficient compared to the commonly used approaches.

Inhibition Clathrin Mediated Endocytosis: Pitstop 1 and Pitstop 2 Chimeras.

Twenty-five chimera compounds of Pitstop 1 and 2 were synthesised and screened for their ability to block the clathrin terminal domain-amphiphysin protein-protein interaction (NTD-PPI using an ELISA) and clathrin mediated endocytosis (CME) in cells. Library 1 was based on Pitstop 2, but no notable clathrin PPI or in-cell activity was observed. With the Pitstop 1, 16 analogues were produced with 1,8-naphthalic imide core as a foundation. Analogues with methylene spaced linkers and simple amides showed a modest to good range of PPI inhibition (7.6-42.5 μM, naphthyl 39 and 4-nitrophenyl 40 respectively) activity. These data reveal the importance of the naphthalene sulfonate moiety, with no des-SO3 analogue displaying PPI inhibition. This was consistent with the observed analogue docked poses within the clathrin terminal domain Site 1 binding pocket. Further modifications targeted the naphthalene imide moiety, with the installation of 5-Br (45 a), 5-OH (45 c) and 5-propyl ether (45 d) moieties. Among them, the OH 45 c and propyl ether 45 d retained PPI inhibition, with propyl ether 45 d being the most active with a PPI inhibition IC50=7.3 μM. This is 2x more potent than Pitstop 2 and 3x more potent than Pitstop 1.

Solubility Change Behavior of Fluoroalkyl Ether-Tagged Dendritic Hexaphenol under Extreme UV Exposure.

This study focuses on the discovery of a single-component molecular resist for extreme ultraviolet (EUV) lithography by employing the ionizing radiation-induced decomposition of carbon-fluorine chemical bonds. The target material, DHP-L6, was synthesized by bonding perfluoroalkyl ether moieties to amorphous dendritic hexaphenol (DHP) with a high glass transition temperature. Upon exposure to EUV and electron beam irradiation, DHP-L6 films exhibited a decreasing solubility in fluorous developer media, resulting in negative-tone images. The underlying chemical mechanisms were elucidated by Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy, and nanoindentation experiments. These analyses highlighted the possible electron-induced decomposition of C-F bonds in DHP-L6, leading to molecular network formation via recombination of the resulting C-centered radicals. Subsequent high-resolution lithographic patterning under EUV irradiation showed that DHP-L6 could create stencil patterns with a line width of 26 nm at an exposure dose of 110 mJ cm-2. These results confirm that single-component small molecular compounds with fluoroalkyl moieties can be employed as patterning materials under ionizing radiation. Nonetheless, additional research is required to reduce the relatively high exposure energy for high-resolution patterning and to enhance the line-edge roughness of the produced stencil.

Effect of ether chain and isomerism on surface and antimicrobial activity of mono- and dicationic imidazolium-based surface-active ionic liquids

A series of 16 imidazolium-based surface-active ionic liquids (SAILs) were synthesized. The designed SAILs, consisted of either one amphiphilic center, 3-alkoxymethyl-1-benzylimidazolium or 3-alkoxymethyl-1-benzyl-2-methylimidazolium, and two amphiphilic centers, 3,3′-[α,ω-(dioxaalkane)]bis(1-benzylimidazolium) or 3,3′-[α,ω-(dioxaalkane)]bis(1-benzyl-2-methylimidazolium). These compounds were investigated in terms of thermal analysis, ability to self-organize to micelles, and antimicrobial activity. The insertion of an ether moiety in the alkyl side or spacer chain favored adsorption at the air–water interface and micellization in the bulk solution when compared to commercial chloride surfactants. The results showed that attachment of a methyl group to the imidazolium ring led to lower the critical micelle concentration (CMC) than lengthening the alkyl chain or spacer in the imidazolium cation. Additionally, biological activity increased with increasing hydrophobicity of the compounds. The methylation of the imidazole ring at positions 2 and 2′ yielded in a notable increase in bacteriostatic activity, especially against Gram-positive bacteria, notably the Staphylococcus aureus strains. It has been demonstrated that minor structural modifications, specifically substituting the imidazole ring instead of elongating the alkyl chain or spacer, can modify the micellization and aggregation behavior, leading to differences in both the efficacy and variety of antimicrobial activity of amphiphilic SAILs.

Optimization of the Structural Rigidity of a Deep‐NIR Scaffold for Bioimaging

Bright deep‐NIR dyes are actively sought after for their potential in fluorescence‐guided surgery and disease theranostics. The major bottleneck lies with the rigidification of the conjugative backbone to suppress non‐radiative deactivation. EC5 is a notable deep‐NIR absorbing/emitting scaffold, which we first reported in 2017. We recently discovered that its diphenyl ether moiety exhibited structural freedom, which was detrimental to its fluorescence brightness. We proposed to enhance the structural rigidity of EC5 via ring‐contraction, i.e., changing the diphenyl ether moiety of EC5E into a biphenyl of EC5B, its low‐frequency normal modes were largely suppressed as predicted by theoretical calculations, and a 55.0% increase of fluorescence brightness in CH2Cl2 was rendered experimentally. The bright EC5B was feasible for high‐contrast in vivo imaging. EC5B has broad potential in practical biomedical applications.

Acidity of saturated (hetero)cyclic α-fluoro carboxylic acids and lipophilicity of their amide derivatives

Analysis of the physicochemical parameters of saturated (hetero)cyclic carboxylic acids and their α-fluorinated analogues is described. Measured pKa values revealed a significant influence of the single fluorine substituent on the compound's acidity (pKa decreased by 1.3–2.4 units). This effect did not demonstrate additivity with electronic effects of other heteroatom (i.e., cyclic ether moiety). On the contrary, lipophilicity (LogP) of the corresponding anilides was almost unaffected upon α-substitution with a fluorine atom and mainly governed by the nature of the (hetera)cycloalkyl substituent. The obtained results suggest that polarization of the C–F bonds themselves does not define the fluorine effect on the compound's lipophilicity.

Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-ol and Related Ether-Alcohols.

Density, viscosity, and self-diffusion coefficients are reported for octan-1-ol and the related ether-alcohols 2-pentoxy-ethan-1-ol, 3-butoxypropan-1-ol, 4-propoxybutan-1-ol, 5-ethoxypentan-1-ol, and 6-methoxyhexan-1-ol covering temperature ranges from 298.15 to 359.15 K. These new data reveal structure-property relationships affected by the presence and the position of the ether moiety in the molecular structure of the ether-alcohols. Compared to octan-1-ol, the presence of the ether moiety causes an increase in intermolecular hydrogen bonding interactions, resulting in higher densities. The increase in density is less pronounced for those ether-octanols that engage in intramolecular hydrogen bonding. As for the effects of the ether moiety on the dynamics, these are generally faster for the ether-alcohols compared to octan-1-ol, suggesting that hydrogen bonding between ether oxygen and hydroxy hydrogen is weaker compared to hydrogen bonding between two hydroxy groups. The activation energies obtained from an Arrhenius analysis are higher for translational motion than for momentum transfer for all alcohols. There are additional finer details across the ether alcohols for these activation barriers. These differences cancel out for the mathematical product of self-diffusion coefficient and viscosity (Dη). The effect of water impurities on the studied properties was also investigated and found to lead to small increases in densities for all alcohols. Viscosities decrease for octan-1-ol and 2-pentoxyethan-1-ol but increase for the other ether-alcohols that can engage in intramolecular hydrogen bonding.

3D-QSAR model-oriented optimization of Pyrazole β-Ketonitrile derivatives with diphenyl ether moiety as novel potent succinate dehydrogenase inhibitors.

Succinate dehydrogenase inhibitor (SDHI) fungicides play important roles in the control of plant fungal diseases. However, they are facing serious challenges from issues with resistance and cross-resistance, primarily attributed to their frequent application and structural similarities. There is an urgent need to design and develop SDHI fungicides with novel structures. Aiming to discover novel potent SDHI fungicides, 31 innovative pyrazole β-ketonitrile derivatives with diphenyl ether moiety were rationally designed and synthesized, which were guided by a 3D-QSAR model from our previous study. The optimal target compound A23 exhibited not only outstanding in vitro inhibitory activities against Rhizoctonia solani with a half-maximal effective concentration (EC50) value of 0.0398 μg mL-1 comparable to that for fluxapyroxad (EC50 = 0.0375 μg mL-1), but also a moderate protective efficacy in vivo against rice sheath blight. Porcine succinate dehydrogenase (SDH) enzymatic inhibitory assay revealed that A23 is a potent inhibitor of SDH, with a half-maximal inhibitory concentration of 0.0425 μm. Docking study within R. solani SDH indicated that A23 effectively binds into the ubiquinone site mainly through hydrogen-bonds, and cation-π and π-π interactions. The identified β-ketonitrile compound A23 containing diphenyl ether moiety is a potent SDH inhibitor, which might be a good lead for novel fungicide research and optimization. © 2024 Society of Chemical Industry.

A General Strategy for Sustainable 3D Printing Based on A Multifunctional Photoinitiator

AbstractA multifunctional photoinitiator is presented, offering precise control over light‐induced polymerization initiation at 450 nm and material degradation at 365 nm. This is accomplished by covalently linking photoactive bis(acyl)phosphane oxide and photocleavable o‐nitrobenzyl ether moieties onto the surface of γ‐cyclodextrin. Upon degradation, the resulting linear polymers can be easily re‐dissolved in their corresponding monomer and re‐cured, exhibiting superior mechanical properties compared to the pristine material. Moreover, this photoinitiator enables the successful 3D printing of intricate and precise structures, representing a promising general strategy for developing recyclable photoresins for 3D printing applications.

A General Strategy for Sustainable 3D Printing Based on A Multifunctional Photoinitiator.

A multifunctional photoinitiator is presented, offering precise control over light-induced polymerization initiation at 450 nm and material degradation at 365 nm. This is accomplished by covalently linking photoactive bis(acyl)phosphane oxide and photocleavable o-nitrobenzyl ether moieties onto the surface of γ-cyclodextrin. Upon degradation, the resulting linear polymers can be easily re-dissolved in their corresponding monomer and re-cured, exhibiting superior mechanical properties compared to the pristine material. Moreover, this photoinitiator enables the successful 3D printing of intricate and precise structures, representing a promising general strategy for developing recyclable photoresins for 3D printing applications.

Discovery of Novel N-Phenyltriazinone Derivatives Containing Oxime Ether or Oxime Ester Moieties as Promising Protoporphyrinogen IX Oxidase Inhibitors.

Protoporphyrinogen IX oxidase (PPO, EC 1.3.3.4) is one of the most important targets for the discovery of green herbicides. In order to find novel PPO inhibitors with a higher herbicidal activity, a series of novel N-phenyltriazinone derivatives containing oxime ether and oxime ester groups were designed and synthesized based on the strategy of pharmacophore and scaffold hopping. Bioassay results revealed that some compounds showed herbicidal activities; especially, compound B16 exhibited broad-spectrum and excellent 100% herbicidal effects to Echinochloa crusgalli, Digitaria sanguinalis, Setaria faberii, Abutilon juncea, Amaranthus retroflexus, and Portulaca oleracea at a concentration of 37.5 g a.i./ha, which were comparable to trifludimoxazin. Nicotiana tabacum PPO (NtPPO) enzyme inhibitory assay indicated that B16 showed an excellent enzyme inhibitory activity with a value of 32.14 nM, which was similar to that of trifludimoxazin (31.33 nM). Meanwhile, compound B16 revealed more safety for crops (rice, maize, wheat, peanut, soybean, and cotton) than trifludimoxazin at a dose of 150 g a.i./ha. Moreover, molecular docking and molecular dynamics simulation further showed that B16 has a very strong and stable binding to NtPPO. It indicated that B16 can be used as a potential PPO inhibitor and herbicide candidate for application in the field.

Synthesis and estrogenic activity of BODIPY-labeled estradiol conjugates

Novel BODIPY–estradiol conjugates have been synthesized by selecting position C-3-O for labeling. The conjugation strategy was based on Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) or etherification. Estradiol derivatives used as azide partners bearing an ω-azidoalkyl function through C4–C8-long linkers have been prepared. CuAAC reactions of estradiol azides with BODIPY alkyne furnished fluorescent 3-O-labeled conjugates bearing the triazole ring as a coupling moiety. Williamson etherifications of 3-O-(ω-bromoalkyl)-17β-estradiol derivatives with BODIPY-OH resulted in labeled conjugates connected with an ether moiety. Interactions of the conjugates with estrogen receptor (ER) were investigated using molecular docking calculations in comparison with estradiol. The conjugates occupied both the classical and alternative binding sites on human ERα, with slightly lower binding affinity to references estradiol and diethystilbestrol. All compounds have displayed reasonable estrogenic activity. They increased the proliferation of ER-positive breast cancer cell line MCF7 contrary to ER-negative SKBR-3 cell line. The most potent compound 13a induced the transcriptional activity of ER in dose-dependent manner in dual luciferase recombinant reporter model and increased progesterone receptor's expression, proving the retained estrogenic activity. The fluorescence of candidate compound 13a co-localised with the ERα. The newly synthesized labeled compounds might serve as good starting point for further development of fluorescent probes for modern biological applications. In addition to studying steroid uptake and transport in cells, e.g. in the processes of biodegradation of estrogen-hormones micropollutants, they could also be utilized in examination of estrogen-binding proteins.

Synthesis, fungicidal activity and molecular docking of novel pyrazole-carboxamides bearing a branched alkyl ether moiety

Succinate dehydrogenase inhibitors are essential fungicides used in agriculture. To explore new pyrazole-carboxamides with high fungicidal activity, a series of N-substitutedphenyl-3-di/trifluoromethyl-1-methyl-1H-pyrazole-4-carboxamides bearing a branched alkyl ether moiety were designed and synthesized. The in vitro bioassay indicated that some target compounds displayed appreciable fungicidal activity. For example, compounds 5d and 5e showed high efficacy against S. sclerotiorum with EC50 values of 3.26 and 1.52 μg/mL respectively, and also exhibited excellent efficacy against R. solani with EC50 values of 0.27 and 0.06 μg/mL respectively, which were comparable or superior to penflufen. The further in vivo bioassay on cucumber leaves demonstrated that 5e provided strong protective activity of 94.3 % against S. sclerotiorum at 100 μg/mL, comparable to penflufen (99.1 %). Cytotoxicity assessment against human renal cell lines (239A cell) revealed that 5e had low cytotoxicity within the median effective concentrations. Docking study of 5e with succinate dehydrogenase illustrated that R-5e formed one hydrogen bond and two π-π stacking interactions with amino acid residues of target enzyme, while S-5e formed only one π-π stacking interaction with amino acid residue. This study provides a valuable reference for the design of new succinate dehydrogenase inhibitor.

Expanding the Scope of Group Transfer Radical Reaction: Toward the Synthesis of Fluorinated Nucleoside Analogues Incorporating Difluorophosphonylated Allylic Ether Moieties.

Scope and limitations of the group transfer radical reaction of diisopropyl iododifluoromethylphosphonate onto carbohydrates and nucleosides are described. This key step allowed us to explore the synthesis of new fluorinated nucleoside analogues containing a difluorophosphonylated allylic ether moiety onto the 2'-position, in purine and pyrimidine series (B = A, C, G, T, U). Indeed, two unprecedented chemical approaches involving a late introduction of either the nucleobase or the fluorinated moiety are discussed.

Highly efficient non-doped organic light emitting diodes based on phenanthreneimidazole derivatives with hot exciton mechanism

Organic light-emitting diodes (OLEDs) promise many advantages for next-generation illumination and future display applications. Developing organic metal-free fluorescent emitter with wide bandgap and high efficiency is both significant and challenging in OLEDs. Here, phenanthroimidazole (PI) unit possessing ultraviolet emission is connected with biphenyl, diphenylmethane and diphenyl ether moieties to construct a series of blue luminogens of PPIDPh, PPIDPhC and PPIDPhO with hot exciton character. PPIDPh with biphenyl substituent at C2 position of PI group exhibits emission peak at 454 nm in non-doped film. The integration of diphenylmethane and diphenyl ether units with PI group in PPIDPhC and PPIDPhO further limits the π-conjugation owing to sp3 hybridized carbon atom and oxygen atom, which results in bluer emission peaking at 433 nm and 437 nm in the aggregated state, respectively. Particularly, the maximum external quantum efficiency (EQEmax) of PPIDPh-based non-doped OLED reaches 10.33 % with CIE coordinates of (0.15, 0.10) and subtle efficiency roll-off of only 7.4 % at high brightness of 1000 cd m−2. The PPIDPhC and PPIDPhO-based non-doped devices display even better color purity with high EQEmax of 8.56 % and 7.90 %, Commission Internationale de ĺEclairage (CIE) coordinates of (0.17, 0.08) and (0.16, 0.08), respectively, matching well with National Television Standards Committee (NTSC) requirement for saturated blue color. Such result is among the best outcomes of non-doped blue fluorescent OLEDs with the same emission color. This result will also shed light on the further development of efficient organic wide bandgap emitter and corresponding high-performance OLED.

Abstract 4481: Enhancing AOH1996 through structure activity relationship exploration for caPCNA inhibition

Abstract Recently, we have developed AOH1996, a small molecule PCNA ligand currently in phase I clinical trial, designed to selectively inhibit the functions of cancer-associated PCNA (caPCNA). Seeking to enhance the potency and selectivity of AOH1996, we conducted an exhaustive Structure-Activity-Relationship (SAR) investigation. Over 100 analogues of AOH1996 were synthesized, systematically modifying its three main components: the naphthyl group, glycine linker, and diphenyl ether. The glycine linker underwent substitution with various natural and unnatural amino acids, while the 1-naphthyl group saw replacements with diverse monocyclic and bicyclic aromatic groups, including quinoline and isoquinoline derivatives. The diphenyl ether moiety was extensively explored by substituting the bridging oxygen with different functional groups (sulfonyl, imido, sulfur, amide), substituting both phenyl rings with various functional groups (fluorine, chlorine, hydroxy, methoxy, methyl, trifluoromethyl), and adopting a nitrogen-walk approach on the terminal phenyl ring to evaluate critical ligand/caPCNA-binding positions. This meticulous effort resulted in the identification of several analogues, such as AOH1160S (featuring a diphenyl thioether group), AOH1996S-4CH3 (with a methyl group at the para-position of the terminal thiophenyl ring), and AOH1996-3CH3 (incorporating an m-methoxy function in the terminal phenyl ring and bridging oxygen), exhibiting similar or superior potency compared to AOH1996. The target binding of these analogues was verified by capturing the binary complex of the more polar version of these analogues in the crystal structure. The synthesis, characterization, and detailed biological activities of these promising AOH analogues will be thoroughly described. Citation Format: Pouya Haratipour, Maryam Zangi, Mahshid Yaghoubi, Long Gu, Jennifer Jossart, John J. Perry, Linda H. Malkas, Robert J. Hickey. Enhancing AOH1996 through structure activity relationship exploration for caPCNA inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4481.

QSAR Studies and Scaffold Optimization of Predicted Novel ACC 2 Inhibitors to Treat Metabolic Syndrome.

Metabolic syndrome is one of the major non-communicable global health hazards of the modern world owing to its amplifying prevalence. Acetyl coenzyme-A carboxylase 2 (ACC 2) is one of the most crucial enzymes involved in the manifestation of this disease because of its regulatory role in fatty acid metabolism. To find novel potent ACC 2 inhibitors as therapeutic potential leads for combating metabolic syndrome. In the present study, a two-dimensional quantitative structure-activity relationship (2D QSAR) approach was executed on biologically relevant thiazolyl phenyl ether derivatives as ACC 2 inhibitors for structural optimization. The physiochemical descriptors were calculated and thus a correlation was derived between the observed and predicted activity by the regression equation. The significant descriptors i.e. log P (Whole Molecule) and Number of H-bond Donors (Substituent 1) obtained under study were considered for the design of new compounds and their predicted biological activity was calculated from the regression equation of the developed model. The compounds were further validated by docking studies with the prepared ACC 2 receptor. The most promising predicted leads with the absence of an H-bond donor group at the substituted phenyl ether moiety yet increased overall lipophilicity exhibited excellent amino acid binding affinity with the receptor and showed predicted inhibitory activity of 0.0025 μM and 0.0027 μM. The newly designed compounds were checked for their novelty. Lipinski's rule of five was applied to check their druggability and no violation of this rule was observed. The compounds designed in the present study have tremendous potential to yield orally active ACC 2 inhibitors to treat metabolic syndrome.

17-Oxime ethers of oxidized ecdysteroid derivatives modulate oxidative stress in human brain endothelial cells and dose-dependently might protect or damage the blood-brain barrier.

20-Hydroxyecdysone and several of its oxidized derivatives exert cytoprotective effect in mammals including humans. Inspired by this bioactivity of ecdysteroids, in the current study it was our aim to prepare a set of sidechain-modified derivatives and to evaluate their potential to protect the blood-brain barrier (BBB) from oxidative stress. Six novel ecdysteroids, including an oxime and five oxime ethers, were obtained through regioselective synthesis from a sidechain-cleaved calonysterone derivative 2 and fully characterized by comprehensive NMR techniques revealing their complete 1H and 13C signal assignments. Surprisingly, several compounds sensitized hCMEC/D3 brain microvascular endothelial cells to tert-butyl hydroperoxide (tBHP)-induced oxidative damage as recorded by impedance measurements. Compound 8, containing a benzyloxime ether moiety in its sidechain, was the only one that exerted a protective effect at a higher, 10 μM concentration, while at lower (10 nM- 1 μM) concentrations it promoted tBHP-induced cellular damage. Brain endothelial cells were protected from tBHP-induced barrier integrity decrease by treatment with 10 μM of compound 8, which also mitigated the intracellular reactive oxygen species production elevated by tBHP. Based on our results, 17-oxime ethers of oxidized ecdysteroids modulate oxidative stress of the BBB in a way that may point towards unexpected toxicity. Further studies are needed to evaluate any possible risk connected to dietary ecdysteroid consumption and CNS pathologies in which BBB damage plays an important role.

Development of Fluorescent Chemosensors for Calcium and Lead Detection.

In the present work, several coumarin-3-carboxamides with different azacrown ether moieties were designed and tested as potential luminescent sensors for metal ions. The derivative containing a 1-aza-15-crown-5 as a metal chelating group was found to yield the strongest response for Ca2+ and Pb2+, exhibiting an eight- and nine-fold emission increase, respectively, while other cations induced no changes in the optical properties of the chemosensor molecule. Job's plots revealed a 1:1 binding stoichiometry, with association constants of 4.8 × 104 and 8.7 × 104 M-1, and limits of detection of 1.21 and 8.04 µM, for Ca2+ and Pb2+, respectively. Computational studies suggest the existence of a PET quenching mechanism, which is inhibited after complexation with each of these two metals. Proton NMR experiments and X-ray crystallography suggest a contribution from the carbonyl groups in the coumarin-3-carboxamide fluorophore in the coordination sphere of the metal ion.

Stereoselective synthesis of 6/7/6-fused heterocycles with multiple stereocenters via an internal redox reaction/inverse electron-demand hetero-Diels-Alder reaction sequence.

A highly stereoselective synthesis of fused heterocycles with multiple stereocenters via an internal redox reaction/inverse electron-demand hetero-Diels-Alder (IEDHDA) reaction sequence is described. The present reaction sequence has three interesting features: (1) complete control of two potentially competitive processes, i.e., hetero-Diels-Alder reaction and [1,5]-hydride shift; (2) one-shot construction of the complicated 6/7/6-fused heterocyclic structure having multiple stereocenters; and (3) high control of its stereoselectivity. When alkenylidene barbiturates with an allyl benzyl ether moiety were treated with a catalytic amount of Sc(OTf)3 and 2,2'-bipyridine, the internal redox reaction/IEDHDA reaction proceeded successively to afford 6/7/6-fused heterocycles in good chemical yields with good to excellent diastereoselectivities.