Described in this paper are the synthesis and structure of novel and edge‐functionalized zigzag hydrocarbon belts. A stepwise “fjord‐stitching” strategy featuring repetitive intramolecular acylation ...reactions of a resorcin4arene derivative as the key steps afforded a biscarbonyl‐functionalized octahydrobelt8arene product. Facile ketone reduction with NaBH4 and nucleophilic addition with n‐butyllithium produced secondary and tertiary alcohol‐containing molecular belts, respectively. Selective oxidation reactions of biscarbonyl‐bearing octahydrobelt8arene with m‐CPBA and (PhSeO)2O furnished the corresponding lactone‐ and 1,4‐quinone‐embedded molecular belts. Depending on the functional groups on the edges, the acquired belt molecules adopt different shapes such as square prism, truncated cone, and elliptical cylinder.
Connecting parts of a resorcin4arene derivative through stepwise intramolecular acylation, reduction, and intramolecular acylation reactions produces a diketone‐bearing zigzag hydrocarbon belt. Further chemical modifications result in the formation of diverse functional molecules with different belt structures.
Hydrocarbon belts have drawn great attention because of their unique structures and tantalizing properties. Although a few belts and heteroatom‐doped analogs have been synthesized, belt molecules ...containing non‐hexagonal rings remain rare. Herein we report the construction and application of unprecedented zigzag‐type hydrocarbon belts which contain functionalized eight‐membered rings. The synthesis features fourfold intramolecular acylation reactions of resorcin4arene‐derived intermediates, which affords C4‐symmetric tetrabenzobelt4arene4cyclooctatrienones. Stereoselective ketone reduction with LiAlH4 and nucleophilic addition with alkynyllithiums provide the corresponding tetrahydroxylated belts. The tetraol and its methyl ether are powerful and selective hosts to form 2 : 1 and 1 : 1 complexes with cesium ion, respectively, with binding constants up to (1.71±0.33)×1011 M−2 and (1.50±0.16)×106 M−1. In addition, enantiopure C4‐symmetric belts can emit CPL with |glum| being around 0.01.
Zigzag‐type hydrocarbon belts which contain functionalized eight‐membered carbocyclic rings are synthesized by stitching up all fjords of resorcin4arene derivatives through fourfold intramolecular acylation reactions and subsequent transformations of ketones. They are powerful and selective hosts to capture cesium ion to form 1 : 1 and 2 : 1 host–guest complexes with binding constants being up to 1.5×106 M−1 and 1.7×1011 M−2, respectively.
Under the catalysis of PdBr
2
and a chiral phosphoramidite ligand, the upper-rim mono (2-bromoaroyl)-substituted calix4arene derivatives underwent a facile enantioselective desymmetrization reaction ...to afford 9
H
-fluorene-embedded inherently chiral calixarenes in good yields with excellent enantioselectivities. The transannular dehydrogenative arene-arene coupling reaction proceeded most probably through an oxidative addition of the C
aryl
-Br bond to a ligated palladium catalyst followed by a sequence of an enantioselective 1,5-palladium migration and an intramolecular C-H arylation sequence. This new family of inherently chiral calixarenes possesses unique chiroptical properties thanks to their highly rigid structure induced by the 9
H
-fluorene segment.
Reported here is the catalytic enantioselective desymmetrization of calixarene skeletons for the construction of inherently chiral calixarenes through a transannular arene-arene dehydrogenative coupling reaction.
We report in this communication the synthesis, structure, and application of a novel type of hydrocarbon belts. Starting from inexpensive and easily available resorcinnarenes, a closing-all-fjords ...strategy featuring exhaustive triflation of phenolic hydroxyl groups followed by consecutively the transition-metal-catalyzed vinylation and intramolecular olefin metathesis allowed facile construction of beltnarenentropilidenes (n = 4, 6), which adopt double-stranded macrocyclic belt structures with unique truncated cone cavities. Selective hydrogenation reactions of olefin and benzene subunits led to diverse hydrocarbon belts with varied structures. Moreover, the resulting molecular belts acted as synthetic host materials to include selectively small molecules such as nitromethane and p-xylene.
Fabricating a strain sensor that can detect large deformation over a curved object with a high sensitivity is crucial in wearable electronics, human/machine interfaces, and soft robotics. Herein, an ...ionogel nanocomposite is presented for this purpose. Tuning the composition of the ionogel nanocomposites allows the attainment of the best features, such as excellent self‐healing (>95% healing efficiency), strong adhesion (347.3 N m−1), high stretchability (2000%), and more than ten times change in resistance under stretching. Furthermore, the ionogel nanocomposite–based sensor exhibits good reliability and excellent durability after 500 cycles, as well as a large gauge factor of 20 when it is stretched under a strain of 800–1400%. Moreover, the nanocomposite can self‐heal under arduous conditions, such as a temperature as low as −20 °C and a temperature as high as 60 °C. All these merits are achieved mainly due to the integration of dynamic metal coordination bonds inside a loosely cross‐linked network of ionogel nanocomposite doped with Fe3O4 nanoparticles.
An ionogel nanocomposite with the combined features of excellent autonomous self‐healing, strong adhesion, high stretchability, and strain sensitivity is fabricated. A conformal strain sensor based on the nanocomposite is demonstrated by changing electrical resistance with special distortion, like arbitrary curved and moving surfaces of a balloon with large inflation. The proof‐of‐concept strain sensor holds great potential for exploring various conformal mechanical sensor systems.
Reaction of isonitriles with 3‐(arylamino)isobenzofuran‐1(3H)‐ones in the presence of a catalytic amount of an octahydro (R)‐binol‐derived chiral phosphoric acid afforded ...3‐oxo‐2‐arylisoindoline‐1‐carboxamides in high yields with good to high enantioselectivities. An enantioselective Ugi four‐center three‐component reaction of 2‐formylbenzoic acids, anilines, and isonitriles was subsequently developed for the synthesis of the same heterocycle. Mechanistic studies indicate that the enantioselectivity results from the dynamic kinetic resolution of the primary Ugi adduct, rather than from the C−C bond‐forming process. The resulting heterocycle products are of significant medicinal importance.
Ugi for real: Reaction of isonitriles (A) with 3‐(arylamino)isobenzofuran‐1(3H)‐ones (B) in the presence of a catalytic amount of chiral phosphoric acid (CPA) afforded 3‐oxo‐2‐arylisoindoline‐1‐carboxamides (C) in high yields with good to high enantioselectivities. An enantioselective Ugi multicomponent reaction of D, E, and A was subsequently developed for the synthesis of the same heterocycle C.
We report herein a strategy to construct enantiopure inherently chiral macrocycles, ABCD-type heteracalix4aromatics, through a catalytic enantioselective intramolecular C–N bond forming reaction. A ...chiral ligand-palladium complex was found to efficiently induce the inherent chirality of molecules during the macrocyclization process with ee values up to >99%. The resulting ABCD-type heteracalix4aromatics displayed excellent and pH-triggered switchable electronic circular dichroism and circularly polarized luminescence properties.
Despite the aesthetically appealing structures and tantalizing physical and chemical properties, zigzag hydrocarbon belts and their heteroatom‐embedded analogues remain challenging synthetic targets. ...We report herein the synthesis of diverse O/N‐doped zigzag hydrocarbon belts based on selective bridging of the fjords of resorcin4arene derivatives through intramolecular SNAr and palladium‐catalyzed intermolecular C−N bond formation reactions. Preorganized conformations of mono‐macrocyclic, half‐belt and quasi‐belt compounds were revealed to facilitate cyclization reactions to construct heteroatom‐linked octahydrobelt8arenes. The acquired products had strained square‐prism‐shaped belt structures in which all six‐membered heterocyclic rings adopted an unusual boat conformation with equatorially configured alkyl groups. The unprecedented heteroatom‐bearing belts also exhibited different photophysical and redox properties to those of octahydrobelt8arene analogues.
Bridging all fjords of resorcin4arene derivatives by means of a macrocyclic‐conformation‐facilitated intramolecular nucleophilic substitution reaction and palladium‐catalyzed intermolecular C−N cross‐coupling led to the production of unprecedented oxygen‐ and nitrogen‐doped zigzag hydrocarbon belts (see structure). The heteroatom‐embedded belts exhibited markedly different photophysical and redox properties to those of their hydrocarbon analogues.
Tetrahomocorona2arene2tetrazines were constructed by means of a fragment coupling strategy based on nucleophilic aromatic substitution reaction starting from 3,6‐dichlorotetrazine and o‐, m‐, and ...p‐bis(hydroxymethyl)benzenes. The unprecedented macrocycles gave rectangular box‐like cavities with tunable cavity sizes and deficient electronic properties depending on the substitution pattern of phenylene. Due to anion–π interactions, they formed complexes selectively with azide and thiocyanate owing to complementary shapes between host and guest.
Just fit! Tetrahomocorona2arene‐2tetrazines, which contain rectangular box‐like cavities with tunable cavity sizes and deficient electronic properties, formed complexes selectively with azide and thiocyanate. This selectivity is due to complementary shapes between host and guest while forming anion–π interactions.
