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In recent years, the activation of unactivated alkyl chlorides through light-induced processes has emerged as a promising field in radical chemistry, and has led to new transformations in organic synthesis. Direct utilization of alkyl chlorides as C(sp3)-hybridized electrophiles enables the facile construction of carbon–carbon and carbon–heteroatom bonds. Furthermore, recent studies in medicinal chemistry indicate that their presence is associated with high levels of success in clinical trials. This review summarizes the recent advances in the photoinduced activation of unactivated alkyl chlorides and discusses the mechanistic aspects underlying these reactions. We anticipate that this review will serve as a valuable resource for researchers in the field of unactivated chemical bond functionalization, and inspire considerable developments in organic chemistry, drug synthesis, materials science and other related disciplines. [ABSTRACT FROM AUTHOR]

Deuterated chemicals are becoming irreplaceable in pharmaceutical engineering, material science and synthetic chemistry. Many excellent reviews have discussed acid/base-dependent or metal-catalyzed deuteration reactions, but radical deuterations have been discussed less. With the development of radical chemistry, there has been a rapid growth in radical deuterium-labelling technology. Diverse mild, cheap and efficient strategies for deuterium atom installation have been reported, and this review summarizes the recent achievements of radical deuteration classified by the reaction types. [ABSTRACT FROM AUTHOR]

We report a general, practical and scalable hydroacylation reaction of ethylene with aromatic carboxylic acids with the synergistic combination of nickel and photoredox catalysis. Under ambient temperature and pressure, feedstock chemicals such as ethylene can be converted into high-value-added aromatic ketones in moderate to good yields (up to 92%) with reaction time of 2 – 6 hours. [ABSTRACT FROM AUTHOR]

An efficient photoredox radical borylation of electron-deficient Morita–Baylis–Hillman type alkenes is achieved to afford multi-functionalized allylic boranes. The reaction demonstrates a wide substrate scope and showcases excellent functional group tolerance. It has advantages over the traditional ionic hydroboration methods in the construction of allylic boranes in terms of simple operation, mild conditions, and step-economy. [ABSTRACT FROM AUTHOR]

A relay photoredox catalysis strategy concomitant with [1,5] hydrogen atom transfer has been applied in the construction of a biologically important indolo[2,1-a]isoquinoline framework via a cascade reaction. This reaction enables double C(sp3)–H bond functionalization and formation of two carbon–carbon double bonds from readily available starting materials in an efficient and step-economical manner. [ABSTRACT FROM AUTHOR]

The remote radical migration strategy has gained considerable momentum. During the past three years, we have witnessed the rapid development of sustainable and practical C–C and C–H bond functionalization by means of long-distance 1,n-radical migration (n = 4, 5, 6) events. Its advent brings our chemical community a new platform to deal with the challenging migration transformations and thus complements the existing ionic-type migration protocols. In this review, the recent achievements in distal radical migration triggered C–C and C–H bond functionalization are summarized. [ABSTRACT FROM AUTHOR]

A photosensitizer-free, highly efficient sunlight-promoted tandem [3+2]/[4+2] annulation of unsaturated α-bromocarbonyls with o-alkynylanilines was developed, and allowed for convenient synthesis of fused benzobicyclic skeletons. The reaction was clean and practical in mild conditions and showed excellent functional group compatibility. [ABSTRACT FROM AUTHOR]

The direct reduction of carboxylic acids to aldehydes with hydrosilane was achieved through visible light photoredox catalysis. The combination of both single electron transfer and hydrogen atom transfer steps offers a novel and convenient approach to selective reduction of carboxylic acids to aldehydes. The method also features mild conditions, high yields, broad substrate scope, and good functional group tolerance, such as alkyne, ester, ketone, amide and amine groups. [ABSTRACT FROM AUTHOR]

Chiral supramolecular assemblies (BNS–BPP) can be self-assembled by electrostatic and π–π stacking interactions between the chiral binaphthyl sulphonate (BNS) anion and the achiral bipyrene-based pyridinium (BPP) cation chromophore. BNS–BPP can exhibit strong CD and circularly polarized luminescence (CPL) signals, and the dissymmetry factor glum values can be up to 0.079. [ABSTRACT FROM AUTHOR]

Herein, two pairs of chiral 1,8-naphthalimide-based enantiomers incorporating d/l-alanine and pyrene fluorophore moieties were designed and synthesized. The fluorescence emission gradually changes from bright-yellow to red when the fraction of the poor solvent methanol increases from 0 to 99 vol%. No obvious circular dichroism (CD) and circularly polarized luminescence (CPL) signals could be observed in the CHCl3 solution. Interestingly, d/l-1 can exhibit a stronger red-colored CPL response signal as compared to d/l-2 at fm = 99% in the aggregate state; this is due to the formation of regular and orderly self-assembled nanonetworks in the aggregate state via intermolecular π–π interactions. Moreover, the optical anisotropy factor (glum) could reach a value as high as 0.013. [ABSTRACT FROM AUTHOR]

A general and efficient visible-light photoredox-catalyzed cascade annulation of 2-ethynylaldehyde hydrazones with α-bromo-carbonyls for the synthesis of various cyclohexylidene-hydrazine-fused polycyclic compounds is described. This protocol is characterized by a broad substrate scope, mild conditions and amenability to gram-scale synthesis. [ABSTRACT FROM AUTHOR]

A new method for the synthesis of 3-arylindoles has been developed by visible light mediated dual gold/photoredox catalysis. This transformation has many features such as cascade catalysis, high efficiency, redox-neutral reaction conditions and good functional group tolerance. The reaction proceeds through the photoredox-promoted formation of an electrophilic arylgold(iii) intermediate that undergoes coupling with the arylamine nucleophile. [ABSTRACT FROM AUTHOR]

The functionalization of a cascade of C(sp2)–H/C(sp3)–H bonds in aldehyde hydrazones with simple 2,2-dibromo-1,3-dicarbonyls was achieved via visible-light photoredox catalysis. This method, which involves free radical addition, polar crossover and 6π electrocyclic reaction, provides an efficient approach for the synthesis of complex fused dihydropyrazoles and related derivatives with moderate to good yields and excellent regioselectivity under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Visible light induced photoredox catalysis is an efficient method for radical activation. Herein, we report the photoredox catalysis involving an intramolecular radical–radical coupling reaction that proceeds through a biradical intermediate. This protocol represents a new synthetic route to construct multi-substituted N-heterocycles. Four, five and six-membered N-heterocyclic structures with a quaternary carbon center are accessible under mild conditions. [ABSTRACT FROM AUTHOR]

The TBPB promoted tandem oxidative C(sp3)–H bond functionalization of simple alkanes/alkylation-initiated dearomatization of N-phenyl-cinnamamides is reported, providing a direct method for the synthesis of alkylated 1-azaspiro[4.5]decanes with excellent regioselectivity and diastereoselectivity. The formation of two C(sp3)–C(sp3) bonds and construction of a spirodienone motif are involved in one step. [ABSTRACT FROM AUTHOR]

Three new boron ketoiminate-based conjugated polymers P1, P2, and P3 were designed and synthesized through the Sonogashira coupling reaction of 4,6-bis(4-bromophenyl)-2,2-difluoro-3-phenyl-2H-1,3,2-oxazaborinin-3-ium-2-uide (M1) with 1,4-diethynyl-2,5-bis(octyloxy)benzene (M2), 3,6-diethynyl-9-octyl-9H-carbazole (M3) and 3,7-diethynyl-10-octyl-10H-phenothiazine-S,S-dioxide (M4), respectively. All the resulting polymers showed obvious aggregation-induced emission (AIE) behaviours. Interestingly, it was found that a great difference in the electron-donating abilities of the D–A type polymer linkers can lead to the unique AIE behaviour of the alternating polymers in the aggregate state, which provides us with a practical strategy to design tunable AIE-active conjugated polymers. Most importantly, studies on MCF-7 breast cancer cell imaging revealed that the nanoparticles fabricated from the conjugated polymers could serve as promising fluorescent probes with low cytotoxicity and high photostability. [ABSTRACT FROM AUTHOR]

Two AIE-active chiral BINOL-based O-BODIPY enantiomers (R/S-5) were synthesized and showed mirror-image red-color CPL induced via intramolecular energy transfer. The chiroptical properties of the molecules indicate that the chirality of electronic ground and excited states is stable and independent of aggregation. [ABSTRACT FROM AUTHOR]

In this study, N-doped carbon dots (NCDs) could be prepared by using glycerol as the carbon source and ethylenediamine as a nitrogen doped molecule through a one-step microwave irradiation method. The resulting NCD probes could exhibit linear fluorescence response to Pb2+ at a detection limit as low as 15.0 nM, which could be applied for trace levels of direct pb2+ recognition. [ABSTRACT FROM AUTHOR]

A novel visible light promoted carbodifluoroalkylation of allylic alcohols is disclosed. A series of difluoro 1,5-dicarbonyl compounds were obtained through a tandem radical addition and 1,2-aryl migration process. Mechanistic analysis indicated that the 1,2-aryl rearrangement proceeded via a radical intermediate. [ABSTRACT FROM AUTHOR]

A novel approach to obtain functionalized tetrazoles by a [3+2] cycloaddition of azide with aldehyde hydrazone is reported. This reaction features a broad substrate scope and mild reaction conditions through an aminyl radical-polar crossover strategy. [ABSTRACT FROM AUTHOR]

Three novel donor–π–acceptor (D–π–A) type chiral polymers P1, P2, and P3 could be synthesized from diiodo-substituted chiral boron-dipyrromethene (BODIPY) derivative (M-1) with 2,7-diethynyl-9,9-dioctyl-9H-fluorene (M-2), 3,6-diethynyl-9-octyl-9H-carbazole (M-3), and 3,7-diethynyl-10-dodecyl-10H-phenothiazine (M-4) via a Pd-catalyzed Sonogashira coupling reaction, respectively. From the choice of the three different donor structures, the three chiral BODIPY-based conjugated polymers can exhibit a red fluorescent emission centered at around 624–650 nm, with tunable band gaps in the range 1.56–1.96 eV, respectively. Interestingly, compared with the anisotropy (r = 0.005) and the CPL dissymmetry factor (glum < 0.01) of the chiral BODIPY small molecule as the counterpart, the three chiral polymers can exhibit a high r (up to 0.10 for P1) and a large glum (up to 0.32 for P2), which can be attributed to the interchain π–π stacking effect and the well-defined chiral arrangement along these polymers backbone. [ABSTRACT FROM AUTHOR]

A tetraphenylethene (TPE)-based chiral polymer (TPETyr) was synthesized by the polymerization of 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene (M-1) and 3′,5′-diiodo-N-α-tert-butoxycarbonyl-O-octyl-l-tyrosine methyl ester (M-2) via Sonogashira cross-coupling. Interestingly, the generated luminogen emits weak fluorescence in THF solution, but becomes strongly luminescent as nanoparticle suspensions upon addition of water, demonstrating a novel phenomenon of aggregation-induced emission (AIE). The resulting TPETyr can also exhibit a large CPL dissymmetry factor (glum) in both solution and aggregate states. More importantly, the glum can be tuned in the range of 0.44 to 0.08 by changing the content of water in THF solution. [ABSTRACT FROM AUTHOR]

A chiral host L1 incorporating (S)-BINOL and substituted coumarin moieties was synthesized via a nucleophilic addition–elimination reaction, and ligand L2 could be obtained by the reduction reaction of the imine-based L1 with NaBH4. The fluorescence responses of chiral compounds L1 and L2 on (l)-/(d)-phenylalaninol were investigated by fluorescence spectra. The fluorescence intensity of L1 in cooperation with (l)-/(d)-phenylalaninol shows a gradual enhancement upon addition of (l)-/(d)-phenylalaninol and keeps a nearly linear correlation with the concentration molar ratios from 1 : 10 to 1 : 180. Stoichiometries and association constants of L1 with (l)-/(d)-phenylalaninol were calculated. The results indicate that chiral sensor L1 can exhibit a remarkable “turn-on” fluorescence enhancement response and excellent enantioselective behaviour for (l)-phenylalaninol by direct visual observation at low concentration, and the value of the enantiomeric fluorescence difference ratio (ef) is 3.07. On the contrary, no obvious fluorescence response and enantioselective recognition effect can be detected for L2 towards either (l)-/(d)-phenylalaninol. [ABSTRACT FROM AUTHOR]

Oxazolo[3,2-a]indolone and spiro[furan-2,2′-indolin]one are synthesized by the visible-light-induced aerobic dearomative reaction of indoles. The common indole tethered alcohol at the N1 or C2 position reacts in a cascade fashion, providing facile access to diverse indolone scaffolds. [ABSTRACT FROM AUTHOR]

A novel visible light mediated radical cyclization of enol lactones with difluoroacyl arenes is presented. The reaction experienced a tandem radical cyclization and tolerated a wide range of substrates, resulting in fluorinated γ-butyrolactones in good chemical yield and with excellent diastereoselectivity. [ABSTRACT FROM AUTHOR]

A metal-free radical oxidative decarboxylation/cyclization of acyl peroxides and 2-isocyanobiphenyls was achieved, leading to 6-aryl phenanthridines as well as 6-alkyl phenanthridines in moderate to good yields. The procedure featured simple conditions and was metal-free and base free. It represents a practical approach to access 6-aryl/alkyl phenanthridines. [ABSTRACT FROM AUTHOR]

A new synthetic strategy for C–C bond formation has been developed via a free radical cascade process under metal-free conditions. Activation of inert C(sp3)–H/elimination of SO2/C–C bond formation were achieved in sequence in this system. [ABSTRACT FROM AUTHOR]

A visible-light-induced decarboxylative trifluoromethylation of α,β-unsaturated carboxylic acids, which uses the Togni reagent as the CF3 source is disclosed. The corresponding trifluoromethylated alkenes were obtained in moderate to high yields with excellent functional group tolerance at ambient temperature. Preliminary mechanistic analyses suggest a radical-type mechanism. [ABSTRACT FROM AUTHOR]

An Eu(iii)-containing polymer can exhibit intense induced circularly polarized luminescence (CPL) in the presence of proline. In addition, the optical anisotropy factor (glum) of the polymer for 5D0→7F1/7F2 transition was much higher than that of a single model molecule, which reveals the amplification effect of CPL arising from the conjugated polymer structure. [ABSTRACT FROM AUTHOR]

An elegant approach to quaternary oxindole formation has been developed through a room temperature decarboxylation/radical C–H functionalization by visible-light photoredox catalysis. [ABSTRACT FROM AUTHOR]

A new synthetic approach toward direct C–N bond formation through sp3 C–H activation has been developed under metal-free conditions. Both primary and secondary benzylic C–H substrates could react smoothly with various amines to give only mono-amination products with good to excellent yields. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed decarboxylative C2-acylation of indoles with α-oxocarboxylic acids was achieved. This protocol represents a novel and complementary approach to 2-aroylindoles. [ABSTRACT FROM AUTHOR]

A novel chiral ionic polymer exhibits high fluorescence enantioselectivity towards α-amino acid anions, and its solution appears bright green upon addition of (l)-α-amino acid anions, which can be clearly observed by the naked eye for direct visual enantioselective recognition. [ABSTRACT FROM AUTHOR]

A copper-catalyzed cross-dehydrogenative coupling reaction that involves C–H activation of formamides and N–H activation of N-alkoxy amides has been developed. This protocol affords a novel approach to the synthesis of multisubstituted ureas under mild conditions. [ABSTRACT FROM AUTHOR]

Mg2+can lead to the fluorescence enhancement of a dye molecule as high as 47.3-fold while l-proline acts as a promoter in this multicomponent sensory system. The fluorescence color could be easily detected by the naked eye under a UV-lamp. [ABSTRACT FROM AUTHOR]

Oxidative α-cyanation of tertiary amines is catalyzed by gold complexes with trimethylsilyl cyanide to afford the corresponding α-aminonitriles in the presence of tert-butyl hydroperoxide in good to excellent yields under acid-free conditions at room temperature. [ABSTRACT FROM AUTHOR]