An effective approach to realize the direct methylation of imidazo1,2-
a
pyridines and quinoxalin-2(1
H
)-ones with peroxides under metal-free conditions is described. In this protocol, peroxides ...serve as both the radical initiator and methyl source. Methylated imidazopyridines and quinoxalin-2(1
H
)-ones were smoothly synthesized in moderate to good yields. A free radical reaction mechanism was proposed to describe the methylation process.
An effective approach to realize the direct methylation of imidazo1,2-
a
pyridines and quinoxalin-2(1
H
)-ones with peroxides under metal-free conditions is described.
An effective approach to realize the direct hydroxyalkylation of imidazo1,2-apyridines with alcohols promoted by di-tert-butyl peroxide was described without any metal catalyst. It is the first ...time that the dehydrogenative C(sp3)–C(sp2) coupling of imidazo1,2-apyridines with alcohols occurred regioselectively at the C-5 position of imidazo1,2-apyridines. Multisubstituted imidazopyridine derivatives were smoothly synthesized in moderate to good yields. Through a series of control experiments, a free-radical pathway was proposed to explain the experiment.
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IJS, KILJ, NUK, PNG, UL, UM
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•Metal-free.•H2O2 as oxidant.•Broad substrate scope.•Easy-available and handled thiosulfates.
A novel, efficient, and green protocol to construct C–S bond has been developed via ...HBr/H2O2-mediated sulfenylation of styrenes and 4-hydroxycoumarins leading to unsymmetrical sulfides. Various unsymmetrical sulfides were prepared in one step with moderate to good yields using environmentally-friendly H2O2 as oxidant and HBr as catalyst. Based on the preliminary experimental results, a plausible reaction mechanism was proposed for HBr/H2O2-mediated formation of C–S bond with thiosulfates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Two hands holding a molecule hint at chirality, which exists in three dimensions from the macro‐ to the micro‐world. A new type of chirality is generated by rotating three functional groups to ...different orientations along an axis. An energy curve shows that there are three relatively stable conformations. Beams of light show the molecules can provide polarized light for future research and applications in materials science. More information can be found in the Research Article by Y. Jiao, G. Li and co‐workers (DOI: 10.1002/chem.202400005).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A new synthetic method toward direct C-N bond formation through saturated C-H amination of benzylic hydrocarbons and inactive aliphatic alkanes with primary aromatic amines under an inexpensive ...catalyst/oxidant (Cu/DTBP) system has been developed. Both aminopyridines and anilines could react smoothly with primary and secondary benzylic C-H substrates or cyclohexane to form the corresponding aromatic secondary amines in moderate to good yields. This protocol has the advantages of wide functional group tolerance and use of readily available raw materials.
A new synthetic method toward direct C-N bond formation through saturated C-H amination of benzylic hydrocarbons and inactive aliphatic alkanes with primary aromatic amines under an inexpensive catalyst/oxidant (Cu/DTBP) system has been developed.
In this study, the design and asymmetric synthesis of a series of chiral targets of orientational chirality were conducted by taking advantage of N-sulfinylimine-assisted nucleophilic addition and ...modified Sonogashira catalytic coupling systems. Orientational isomers were controlled completely using alkynyl/alkynyl levers C(sp)-C(sp) axis with absolute configuration assignment determined by X-ray structural analysis. The key structural element of the resulting orientational chirality is uniquely characterized by remote through-space blocking. Forty examples of multi-step synthesis were performed, with modest to good yields and excellent orientational selectivity. Several chiral orientational amino targets are attached with scaffolds of natural and medicinal products, showing potential pharmaceutical and medical applications in the future.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
New chiral targets of orientational chirality have been designed and asymmetrically synthesized by taking advantage of N‐sulfinyl imine‐directed nucleophilic addition/oxidation, Suzuki‐Miyaura, and ...Sonogashira cross‐coupling reactions. Orientation of single isomers has been selectively controlled by using aryl/alkynyl levers C(sp2)‐C(sp) axis and tBuSO2‐ protecting group on nitrogen as proven by X‐ray diffraction analysis. The key structural characteristic of resulting orientational products is shown by remote through‐space blocking manner. Seventeen examples of multi‐step synthesis were obtained with modest to good chemical yields and complete orientational selectivity.
We report herein the design of the asymmetric synthesis of orientational atropisomers via Sonogashira coupling as the key step. This new category of orientational atropisomers is anticipated to have a broad impact on chemical, biomedical, and material sciences in the future.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The first asymmetric catalytic approach to multilayer 3D chirality has been achieved by using Suzuki‐Miyaura cross‐couplings. New chiral catalysts were designed and screened under various catalytic ...systems that proved chiral amide‐phosphines to be more efficient ligands than other candidates. The multilayer 3D framework was unambiguously determined by X‐ray structural analysis showing a parallel pattern of three layers consisting of top, middle and bottom aromatic rings. The X‐ray structure of a catalyst complex, dichloride complex of Pd‐phosphine amide, was obtained revealing an interesting asymmetric environment nearby the Pd metal center. Three rings of multilayer 3D products can be readily changed by varying aromatic ring‐anchored starting materials. The resulting multilayer products displayed strong luminescence under UV irradiation and strong aggregation‐induced emission (AIE). In the future, this work would benefit not only the field of asymmetric synthesis but also materials science, in particular polarized organic electronics, optoelectronics and photovoltaics.
The first asymmetric catalytic approach to multilayer 3D chirality by using Suzuki‐Miyaura cross‐couplings in the presence of new chiral amide‐phosphines is reported. The resulting multilayer products showed strong luminescence under UV irradiation, and displayed strong aggregation‐induced emission (AIE).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Chirality has existed in nature from the early stages of life on Earth. A new form of chirality, multilayer 3D chirality, has been established involving nearly parallel patterns. This work presents ...the first asymmetric catalytic approach to multi‐layer 3D chirality. New complexes of Pd and chiral amide‐phosphine ligands were utilized as catalysts for Suzuki‐Miyaura coupling for assembling various multilayer 3D chiral molecules, which displayed strong luminescence under UV irradiation and strong aggregation‐induced emission (AIE) of different colors. More information can be found in the Full Paper by G. Li et al. (DOI: 10.1002/chem.202100700).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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