Recent developments of ketene dithioacetal chemistry

Highly Stereoselective Synthesis of α-Oxoketene N,X-Acetals (X = O, S, or N) under Mild Conditions

A straightforward synthesis of α-oxoketene N,X-acetals (X = O, S, or N) from β-oxoamides has been described. The oxyphosphonium intermediates are quickly generated in situ from β-oxoamides in the presence of Hendrickson reagent and triflic anhydride (Tf2O) in a chemoselective manner and undergo a chemoselective nucleophilic substitution with phenols, thiophenols, or aromatic amines to deliver the desired products with high stereoselectivity. The one-pot synthetic protocol features readily available starting materials, mild conditions, simple execution, and a wide range of synthetic potentials of the products.

Synthesis of dithioacetals via nucleophilic substitution and their antifungal activity evaluation

A novel dual nucleophilic substitution reaction of dichloromethane with thiols has been developed, which affords dithioacetals in up to 96% yields. This dual substitution reaction with two different nucleophiles is also successfully developed with α-acyloxy sulfides as the product. In addition, in vitro antifungal activity tests against L. theobromae disclose that these α-acyloxy sulfides exhibit excellent antifungal activity with an inhibition rate up to 100 ± 0%. This reaction provides efficient access to potential bioactive dithioacetals from readily available starting materials.

Desulfurative Functionalization of β-Acyl Allylic Sulfides with N-H Free Indoles Highly Regioselective at C3 and N1 Positions: Rapid Access to α-Branched Enones

A regiodivergent allylation of 1H-indoles highly selectively at the C3 and N1 positions with β-acyl allylic sulfides through desulfurative C-C/C-N bond-forming reactions has been developed under mild conditions. Notably, the remarkable site-selective switch can be achieved by a delicate choice of solvents and bases. This cost-efficient method displays a broad substrate scope, good functional compatibility, and excellent site-selectivity, thus offering a divergent synthesis of indole substituted α-branched enones, which possess diverse potential opportunities for further applications and derivatization.

An ICT-based highly fluorescent isoquinoline scaffold for selective Hg(II) detection in real-water samples: Development of a smart, low-cost RGB-Arduino electronic platform

Selective detection and quantification of Hg2+ ions is crucial to minimize health and environmental risks. Fluorescent organic small-molecule probes have been expeditiously utilized owing to their unique set of improved properties. However, isoquinoline core has not been extensively explored as a fluorescence platform partly due to synthetic challenges. Herein, a serendipitously discovered synthetic route to access a small yet highly functionalized novel isoquinoline-based probe, IQ is reported. The synthesis is achieved through the in-situ generation of ammonia, followed by intermolecular [5C + 1 N] aza-annulation reaction with a ketendithioacetal-based precursor, P-IQ. IQ displayed excellent recognition ability towards Hg2+ ions in H2O:ACN (99:1, v/v) via ICT-off fluorescent quenching behavior. Comparative FT-IR, 1H/13C NMR, mass spectral studies, and DFT analyses were carried out to validate the suggested mechanisms. Reversible studies confirm the secondary recognition effect of in-situ generated (IQ + Hg2+) complex on cysteine. The binding constant and LOD were estimated to be 3.7 × 104 M-1 and 0.86 µM, respectively. Further, IQ was utilized to evaluate the mercury ion content in real water samples demonstrating its effectiveness in water quality monitoring. The practical utility of IQ was further explored by developing TLC strips, Whatman filter-paper strips, and a low-cost, portable Arduino-based platform. Arduino microcontroller is interfaced with an RGB sensor to detect color changes and quantify mercury concentration w.r.t. RGB values.

1,3-Dianionic annulation of ketones with ketene dithioacetal: a modified route to 3-aryl/cyclopropyl-5-thiomethyl-phenols and 1-(methylthio)-9,10-dihydrophenanthren-3-ols

A simple and efficient base-mediated [3 + 3] cyclization of 1,3-dianionic ketones with 3,3-bis(methylthio)-1-arylprop-2-en-1-ones was developed to afford 3-hydroxy-biaryls, hydroxy-xylenes, and hydroxy-teraryls. Various tri- and tetra-substituted phenols were prepared from different symmetric and asymmetric ketones. The reaction of 2-(bis(methylthio)methylene)-3,4-dihydronaphthalen-1(2H)-ones with different ketones provided 1-(methylthio)-9,10-dihydrophenanthren-3-ols in very good yield. The scope of the reaction was further extended by the synthesis of cyclopropyl-functionalized phenols. One of the compounds was crystallized, and its structure was confirmed using the single-crystal X-ray approach.

Visible-Light-Promoted Regioselective Hydroborylation of Ketene Dithioacetals with NHC-Boranes

NHC-boranes have been treated as a reliable source of boryl radicals. In this study, regioselective hydroborylation of ketene dithioacetals with NHC-borane was achieved under mild conditions via a visible-light-promoted radical chain process using thiophenol as a proton donor and hydrogen atom transfer. This protocol features a low-cost catalyst, good functional group tolerance, a relatively broad range of substrate scope, and good to excellent yields. Moreover, mechanism of this hydroborylation reaction was preliminarily studied.

Acyl-Ethynylbenziodoxolone (acyl-EBX): Access to Ketene Dithioarylacetals

We report the synthesis of ketene dithioarylacetals in 40-97% yield using thiophenols and acyl-EBXs (ethynylbenziodoxolones) generated in situ from a common hypervalent iodine precursor and alkynyl trifluoroborate salts. The products could be further modified to afford functionalized ketene dithioacetals and various S-substituted heterocycles.

A decade update on the application of β-oxodithioesters in heterocyclic synthesis

The diverse synthesis of heterocyclic compounds has always been one of the popular subjects of organic chemistry. To this end, great efforts have been devoted to developing new reagents and establishing new strategies and methods concerning efficiency, selectivity and sustainability. β-Oxodithioesters and their enol tautomers (i.e., α-enolic dithioesters), as a class of simple and readily accessible sulfur-containing synthons, have been widely applied in the construction of various five- and six-membered heterocycles (e.g., thiophenes, thiopyrans, thiazoles, pyridines and quinolines) and other useful open-chain frameworks. Due to their unique chemical structures, β-oxodithioesters bear multiple reaction sites, which enable them to participate in two-component or multicomponent reactions to construct various heterocyclic compounds. In the past decade, the application of β-oxodithioesters in the synthesis of heterocycles has made remarkable progress. Herein, an update on the recent advances in the application of β-oxodithioesters in the synthesis of heterocycles during the period from 2013 to 2023/06 is provided. According to the different types of rings concerning heteroatoms in products, this review is divided into five sections under discussion including (i) synthesis of sulfur-containing heterocycles, (ii) synthesis of sulfur and nitrogen-containing heterocycles, (iii) synthesis of nitrogen-containing heterocycles, (iv) synthesis of nitrogen and oxygen-containing heterocycles, and (v) modification to other open-chain frameworks.

Trifluoromethylations of (Hetero)arenes and Polarized Alkenes Using Trifluoroacetic Anhydride under Photoredox Catalysis

A novel trifluoromethylation of (hetero)arenes and polarized alkenes using simple trifluoroacetic anhydride (TFAA) as the low price CF₃ source under photoredox catalysis was developed without using additives such as bases, hyperstoichiometric oxidant, or auxiliaries. The reaction showed excellent tolerance, including to some important natural products and prodrugs, even on the gram scale and extended to ketones. This simple protocol provides a practical utilization of TFAA. Several perfluoroalkylations and trifluoromethylation/cyclizations were successfully achieved under identical conditions.

Recent Advances in Alkenyl sp2 C-H and C-F Bond Functionalizations: Scope, Mechanism, and Applications

Alkenes and their derivatives are featured widely in a variety of natural products, pharmaceuticals, and advanced materials. Significant efforts have been made toward the development of new and practical methods to access this important class of compounds by selectively activating the alkenyl C(sp²)-H bonds in recent years. In this comprehensive review, we describe the state-of-the-art strategies for the direct functionalization of alkenyl sp² C-H and C-F bonds until June 2022. Moreover, metal-free, photoredox, and electrochemical strategies are also covered. For clarity, this review has been divided into two parts; the first part focuses on currently available alkenyl sp² C-H functionalization methods using different alkene derivatives as the starting materials, and the second part describes the alkenyl sp² C-F bond functionalization using easily accessible gem-difluoroalkenes as the starting material. This review includes the scope, limitations, mechanistic studies, stereoselective control (using directing groups as well as metal-migration strategies), and their applications to complex molecule synthesis where appropriate. Overall, this comprehensive review aims to document the considerable advancements, current status, and emerging work by critically summarizing the contributions of researchers working in this fascinating area and is expected to stimulate novel, innovative, and broadly applicable strategies for alkenyl sp² C-H and C-F bond functionalizations in the coming years.

Advancement of Phenoxypyridine as an Active Scaffold for Pesticides

Phenoxypyridine, the bioisostere of diaryl ethers, has been widely introduced into bioactive molecules as an active scaffold, which has different properties from diaryl ethers. In this paper, the bioactivities, structure-activity relationships, and mechanism of compounds containing phenoxypyridine were summarized, which may help to explore the lead compounds and discover novel pesticides with potential bioactivities.

Modern Synthesis and Chemistry of Stabilized Ketene N,O-Acetals

Ketene N,O-acetals are robust and versatile synthons. Herein, we outline the synthesis of stable ketene N,O-acetals in the twenty-first century. In addition, we review recent developments in the chemistry of ketene N,O-acetals, as it applies to the vinylogous Mukaiyama aldol reaction, electrolysis, and pericyclic transformations. While dated reports rely on in situ use, modern methods of ketene N,O-acetal synthesis are heavily oriented towards producing products with high ‘bench’ stability; moreover, in the present century, chemists typically enhance the stability of ketene N,O-acetals by positioning an electron-withdrawing group at the β-terminus or at the N-position. As propitious substrates in the vinylogous Mukaiyama aldol reaction, ketene N,O-acetals readily provide polyketide adducts with high regioselectivity. When exposed to electrolysis conditions, the title functional group forms a reactive radical cation and cleanly couples with a variety of activated olefins. Given their electron-rich nature, ketene N,O-acetals act as facile substrates in several rearrangement reactions; further, ketene N,O-acetals reserve the ability to act as either dienophiles or dienes in Diels–Alder reactions. Lastly, ketene N,O-acetals are seemingly more stable than their O,O-counterparts and more reactive than analogous N,N- or S,S-acetals; these factors, in combination, make ketene N,O-acetals advantageous substitutes for other ketene acetal homologues.

1 Introduction

2 Select Methods of Stabilization-Oriented Ketene N,O-Acetal Synthesis

3 Ketene N,O-Acetals in the Vinylogous Mukaiyama Aldol Reaction

4 Ketene N,O-Acetals in Anodic Coupling and Electrochemical Oxidation Reactions

5 Rearrangement and Diels–Alder Reactions of Ketene N,O-Acetals

6 Conclusions, Perspectives, and Directions

Green Tandem [5C + 1C] Cycloaromatization of α-Alkenoyl Ketene Dithioacetals and Nitroethane in Water: Eco-Friendly Synthesis of Ortho-Acylphenols

For the first time, an eco-friendly and sustainable tandem [5C + 1C] cycloaromatization of α-alkenoyl ketene dithioacetals and nitroethane in water for the efficient synthesis of ortho-acylphenols was reported. In refluxing water, a range of α-alkenoyl ketene dithioacetals and nitroethane smoothly underwent tandem Michael addition/cyclization/aromatization reactions in the presence of 2.0 equivalents of DBU to provide various ortho-acylphenols in excellent yields. The green approach to ortho-acylphenols not only avoided the use of harmful organic solvents, which could result in serious environmental and safety issues, but also exhibited fascinating features such as good substrate scope, excellent yields, simple purification for desired products, ease of scale-up, and reusable aqueous medium.

PhIO-Mediated Oxidative C═C Bond Cleavage and Reassembly toward Highly Functionalized Oxazolones

An efficient PhIO-mediated oxidative C═C bond cleavage and reassembly of enaminone toward oxazolone with high regioselectivity has been reported. DFT calculations revealed that the reaction proceeded through an oxygen atom transfer, C═C bond cleavage, alkylthio migration, and reassembly cascade. This strategy is highlighted by high atom and step economy with formation of five bonds in one pot and generation of a high-valued oxazolone skeleton under mild conditions.

Iodine-Mediated Synthesis of 2-(Methylthio)-4H-chromen-4-ones and Study of Their Halogenation Reactions

An efficient iodine-mediated method is developed for the synthesis of functionalized 2-(methylthio)-4H-chromen-4-ones by intramolecular cyclization of easily accessible 1-(2-benzyloxy-aryl)-3,3-bis-methylsulfanyl-propenones. The synthesized chromen-4-ones turn out to be a key precursor for various kinds of chemical reactions. Mechanistically, we observed that iodine-mediated intramolecular cyclization of ketene dithioacetal proceeded through a radical pathway. 3-Halo-2-(methylthio)-4H-chromen-4-ones were achieved via various two- or one-pot halogenation approaches.

The 1,3-dithiol-2-ide carbanion

1,3-Dithiol-2-ide is a fully unsaturated five-membered heterocycle with a carbanion unit between two of the ring sulfur atoms. Derivatives thereof are important intermediates in synthetic protocols for preparing various 1,4-dithiafulvene (DTF) and tetrathiafulvalene (TTF) compounds by Wittig, Horner-Wadsworth-Emmons, or phosphite-mediated olefination reactions. When considering the electronic properties of DTF, one would usually consider this unit as an electron-donating group as it can form a 6π-aromatic 1,3-dithiolium ring by resonance. Yet, in this review, I will move forward a dual character of the DTF by which it can also act as an electron-withdrawing group, involving formation of the 1,3-dithiol-2-ide. In particular, this electronic effect can be used to explain its ability to promote the electrocyclic ring closure of a vinylheptafulvene into a dihydroazulene. This view on the properties of DTF is very much in line with the dual reactivity of ketene dithioacetals that react with both nucleophiles and electrophiles. Moreover, the 1,3-dithiol-2-ide unit was recently generated in the reduction of an extended and quinoid-like TTF where the core became an aromatic carbo-benzene moiety. This aspect is particularly interesting for future design of extended TTFs that can act as both electron donors and acceptors.

Visible-Light-Induced Sulfur-Alkenylation of Alkenes

A visible-light-induced intermolecular sulfur-alkenylation of alkenes, including both activated and unactivated alkenes, is described. This sulfur-alkenylation reaction proceed in a highly regio- and stereospecific manner involving the visible-light-induced conversion of a ketene dithioacetal to the thiavinyl 1,3-dipole intermediate, followed by a formal [3 + 2] cycloaddition and C-S bond cleavage. Furthermore, it is also an efficient approach for the late-stage functionalization of natural products and complex molecules, even being induced by sunlight under ambient conditions.

Single-Pot Preparation of 4-Amino-2-(het)aryl-5-Substituted Thiazoles Employing Functionalized Dithioesters as Thiocarbonyl Precursors

An effective, diversity oriented, one-pot reaction of 4-amino-2-(het)aryl/alkyl-5-functionalized thiazoles has been disclosed, utilizing aryl/heteroaryl/alkyl dithioesters as thiocarbonyl coupling partners in a modified Thorpe-Ziegler type cyclization. The reaction proceeds at room temperature, under mild conditions, in excellent yields, displaying broad functional group compatibility at 2 and 5 positions of thiazoles. This synthetic strategy has been further expanded for the one-pot construction of two highly potent tubulin polymerization inhibitors, i.e., 2-(het)aryl-4-amino-5-(3,4,5-trimethoxyaroyl) thiazoles, in high yields.

Visible-Light-Induced Formation of Thiavinyl 1,3-Dipoles: A Metal-Free [3+2] Oxidative Cyclization with Alkynes as Easy Access to Thiophenes

A visible-light-induced [3+2] oxidative cyclization of various alkynes with easily available ketene dithioacetals as the previously unknown thiavinyl 1,3-dipoles in the presence of an acridine photosensitizer is reported. A series of multisubstituted thiophenes were achieved regioselectively in ≤98% yields under very mild metal-free conditions without other additives. This reaction could tolerate a wide range of substrates and achieve good efficiency in large-scale syntheses. The reaction mechanism and their applications are described in detail to reveal the reactivity of the new 1,3-dipoles and the selectivity of the reactions.

Selectfluor-Promoted Intramolecular N-S Bond Formation of α-Carbamoyl Ketene Dithioacetals in the Presence of Water: Synthesis of Multifunctionalized Isothiazolones

A practical and efficient protocol toward fully substituted isothiazolones through Selectfluor-mediated intramolecular oxidative annulation of α-carbamoyl ketene dithioacetals has been developed in the presence of H₂O and metal-free conditions. Notably, the experimental results reveal that H₂O was crucial to the formation of new N-S bonds and the elimination of alkyl group from the sulfur atom. This protocol provides readily prepared substrates and possesses good functional group tolerance, mild reaction conditions, and operational simplicity, which provides potential access to applications in the pharmaceutical chemistry.

Synthesis, Antibacterial, and Antioxidant Evaluation of Novel Series of Condensed Thiazoloquinazoline with Pyrido, Pyrano, and Benzol Moieties as Five- and Six-Membered Heterocycle Derivatives

A novel synthesis of thiazolo[2,3-b]quinazolines 4(a–e), pyrido[2′,3′:4,5]thiazolo[2,3-b]quinazolines {5(a–e), 6(a–e), and 7(a–e)}, pyrano[2′,3′:4,5]thiazolo[2,3-b]quinazolines 8(a–e), and benzo[4,5]thiazolo[2,3-b]quinazoloine9(a–e) derivatives starting from 2-(Bis-methylsulfanyl-methylene)-5,5-dimethyl-cyclohexane-1,3-dione 2 as efficient α,α dioxoketen dithioacetal is reported and the synthetic approaches of these types of compounds will provide an innovative molecular framework to the designing of new active heterocyclic compounds. In our study, we also present optimization of the synthetic method along with a biological evaluation of these newly synthesized compounds as antioxidants and antibacterial agents against the bacterial strains, like S. aureus, E. coli, and P. aeruginosa. Among all the evaluated compounds, it was found that some showed significant antioxidant activity at 10 μg/mL while the others exhibited better antibacterial activity at 100 μg/mL. The results of this study showed that compound 6(c) possessed remarkable antibacterial activity, whereas compound 9(c) exhibited the highest efficacy as an antioxidant. The structures of the new synthetic compounds were elucidated by elemental analysis, IR, ¹H-NMR, and ¹³C-NMR.

Rhodium-catalyzed enone carbonyl directed C–H activation for the synthesis of indanones containing all-carbon quaternary centers

Rhodium(iii)-catalyzed enone carbonyl directed C–H activation/annulation of α-aroyl ketene dithioacetals with diazo compounds has been realized for the synthesis of β-quaternary indanones.

Transition metal free, green and facile halogenation of ketene dithioacetals using a KX–oxidant system

A facile oxidative halogenation of α-oxo ketene dithioacetals is achieved by using a potassium halide and an oxidant combination under transition metal free conditions at ambient temperature.

Recent Advances in Iodine-Promoted C-S/N-S Bonds Formation

Sulfur-containing scaffold, as a ubiquitous structural motif, has been frequently used in natural products, bioactive chemicals and pharmaceuticals, particularly C-S/N-S bonds are indispensable in many biological important compounds and pharmaceuticals. Development of mild and general methods for C-S/N-S bonds formation has great significance in modern research. Iodine and its derivatives have been recognized as inexpensive, environmentally benign and easy-handled catalysts or reagents to promote the construction of C-S/N-S bonds under mild reaction conditions, with good regioselectivities and broad substrate scope. Especially based on this, several new strategies, such as oxidation relay strategy, have been greatly developed and accelerated the advancement of this field. This review focuses on recent advances in iodine and its derivatives promoted hybridized C-S/N-S bonds formation. The features and mechanisms of corresponding reactions are summarized and the results of some cases are compared with those of previous reports. In addition, the future of this domain is discussed.

Transition-metal mediated carbon-sulfur bond activation and transformations: an update

Carbon-sulfur bond cross-coupling has become more and more attractive as an alternative protocol to establish carbon-carbon and carbon-heteroatom bonds. Diverse transformations through transition-metal-catalyzed C-S bond activation and cleavage have recently been developed. This review summarizes the advances in transition-metal-catalyzed cross-coupling via carbon-sulfur bond activation and cleavage since late 2012 as an update of the critical review on the same topic published in early 2013 (Chem. Soc. Rev., 2013, 42, 599-621), which is presented by the categories of organosulfur compounds, that is, thioesters, thioethers including heteroaryl, aryl, vinyl, alkyl, and alkynyl sulfides, ketene dithioacetals, sulfoxides including DMSO, sulfones, sulfonyl chlorides, sulfinates, thiocyanates, sulfonium salts, sulfonyl hydrazides, sulfonates, thiophene-based compounds, and C[double bond, length as m-dash]S functionality-bearing compounds such as thioureas, thioamides, and carbon disulfide, as well as the mechanistic insights. An overview of C-S bond cleavage reactions with stoichiometric transition-metal reagents is briefly given. Theoretical studies on the reactivity of carbon-sulfur bonds by DFT calculations are also discussed.

ZnCl2 -Catalyzed [4+1] Annulation of Alkylthio-Substituted Enaminones and Enaminothiones with Sulfur Ylides

Concise construction of furan and thiophene units has played an important role in the synthesis of potentially bioactive compounds and functional materials. Herein, an efficient Lewis acid ZnCl₂ catalyzed [4+1] annulation of alkylthio-substituted enaminones is reported, that is, α-oxo ketene N,S-acetals with sulfur ylides to afford 2-acyl-3-aminofuran derivatives. In a similar fashion, [4+1] annulation of the corresponding enaminothiones, that is, α-thioxo ketene N,S-acetals, with sulfur ylides efficiently proceeded to give multisubstituted 3-aminothiophenes. This method features wide substrate scopes as well as broad functional group tolerance, offering a concise route to highly functionalized furans and thiophenes.

Adaptive Covalent Networks Enabled by Dual Reactivity: The Evolution of Reversible Covalent Bonds, Their Molecular Assemblies, and Guest Recognition

Adaptive chemistry allows transformation and selection within molecular networks, and adaptive systems composed of different types of dynamic covalent reactions (DCRs) are challenging. Herein, we demonstrate dual reactivity-based covalent networks encompassing the regulation of and switching between C-N- and C-S-based reversible covalent assemblies. The creation and exchange of C-N- or C-S-derived assemblies exhibiting diverse architectures, including linear structures, macrocycles, and cages, were achieved. The shift of reactivity then permitted the interconversion between C-N- and C-S-containing assemblies. Moreover, the adaption of intramolecular and intermolecular scaffolds was feasible via linker design. The latent hemiaminal chirality center offered a pathway for the induction of chirality within assemblies. Finally, switchable structural change and controlled extraction of ions were realized with Hg²⁺ as a guest for macrocycles. The remarkable complexity of networks described herein could open the door for the utility in sophisticated functional systems.

Crystal structure, Hirshfeld surfaces, topology, energy frameworks and dielectric studies of 1-(2-chlorophenyl)- 3,3-bis(methylthio)prop-2-en-1-one

The title compound 1-(2-chlorophenyl)-3,3-bis(methylthio)prop-2-en-1-one (1) have been synthesized, crystallized and characterized using FT-IR, 1H NMR, 13C NMR, LCMS and confirmed by single crystal X-ray diffraction method. In addition, the intermolecular interactions in the crystal structure are analyzed using Hirshfeld surfaces computational method. The (1) crystallizes in a monoclinic crystal system (space group P 21/ c) with cell parameters a = 17.0132(9) Å, b = 8.6521(4) Å, c = 8.2815(7) Å, β = 95.512(6) ° and Z = 4. Intermolecular hydrogen bonds/interactions of the type C · · · H · · · O, C–H · · · S, C–H · · · Cg and C–Cl · · · Cg stabilize the crystal structure. The intermolecular interactions responsible for crystal packing are analyzed using Hirshfeld surfaces computational method, 2D finger print plots, electrostatic potential surfaces, toplogy surfaces [curvedness (C) and shape index (S), enrichment ratio (E) and 3D energy frameworks]. In addition the dielectric studies were performed for the title molecule. The crystal structure database (CSD) analysis was carried out for structural conformation and crystal packing confirmation. Overall structural studies confirmed that the intermolecular interactions of the type S · · · S chalocogen bonds are involved in crystal packing in addition to the C11–H11 · · · O1, C10–H10B · · · O1, two C10–H10 · · · S1, C4–H11 · · · Cg1 and C1–Cl1 · · · Cg1 interactions.

Photoinduced C(sp2)-H/C(sp2)-H Cross-Coupling of Alkenes: Direct Synthesis of 1,3-Dienes

A highly concise route to substituted 1,3-dienes from vinylarenes and ketene dithioacetals under photoinduced cross-coupling reaction is described. The reaction proceeded in a highly regio- and stereoselective manner and showed broad functional group tolerance. More than 35 substituted 1,3-dienes were synthesized with good to excellent yields through the construction of the Csp²-Csp² bond without using noble metal and external oxidants, and natural sunlight could also induce the reaction to afford gram-scale synthesis under ambient conditions.

A [5 + 1] annulation strategy for the synthesis of multifunctional biaryls and p-teraryls from 1,6-Michael acceptor ketene dithioacetals

A [5 + 1] annulation approach was used to access multifunctional biaryls and p-teraryls from ketene dithioacetals.

Straightforward chemoselective access to unsymmetrical dithioacetals through a thiosulfonate homologation-nucleophilic substitution sequence

A two-step electrophilic sulfur homologation strategy for building up unsymmetrical dithioacetals.