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A Cu-promoted highly chemoselective dimerization of 5-aminopyrazoles to produce pyrazole-fused pyridazines and pyrazines is reported. The protocol generates switchable products via the direct coupling of C-H/N-H, C-H/C-H and N-H/N-H bonds, with the merits of broad substrate scope and high functional group compatibility. Gram-scale experiments demonstrated the potential applications of this reaction. Moreover, the preliminary fluorescence results uncovered that dipyrazole-fused pyridazines and pyrazines may have some potential applications in materials chemistry.

Skeleton editing for heteroarenes, especially pyrazoles, is challenging and remains scarce because these non-strained aromatics exhibit inert reactivities, making them relatively inactive for performing a dearomatization/cleavage sequence. Here, we disclose a cycloaddition-induced scaffold hopping of 5-hydroxypyrazoles to access the pyrazolopyridopyridazin-6-one skeleton through a single-operation protocol. By converting a five-membered aza-arene into a five-unit spine of a 6/6 fused-bicyclic, this work unlocks a ring-opening reactivity of the pyrazole core that involves a formal C = N bond cleavage while retaining the highly reactive N-N bond in the resulting product. A [4 + 2] cycloaddition of a temporarily dearomatized 5-hydroxypyrrole with an in situ generated aza-1,3-diene, followed by oxidative C-N bond cleavage, constitutes the domino pathway. A library of pyrazolopyridopyridazin-6-ones, which are medicinally relevant nitrogen-atom-rich tricyclics, is obtained efficiently from readily available materials., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

We report an unconventional I 2 -catalyzed cascade reaction for the synthesis of angular triquinane derivatives with a fused heterocycle skeleton, leveraging enaminones and anilines as simple acyclic precursors. The key to success lies in I 2 functioning as a polar-reversal catalyst, which alters the reactivity at the α-position of the enaminone and facilitates the first hexa-functionalization of an enaminone along with the formation of highly congested continuous stereocenters.

The synthesis of N-heterocycles has received extensive attention from scientists considering their important role in organic synthesis, pharmaceuticals, and materials chemistry. α-Amino acids (α-AAs), both natural and non-natural, are structurally diverse, containing basic amino groups, acidic carboxyl groups, and various side-chain R groups in a single molecule. Given their structural properties and wide range of sources, they have undoubtedly become suitable synthetic building blocks for organic synthesis. However, conventional transformations of amino acids (AAs) focus on the amino and carboxyl groups independently. Conversions for these two prominent functional groups generally do not affect both their alpha positions and their branched chains. Over the past decade, with the application of iodine (I 2 ) in the field of heterocyclic synthesis, the use of α-AAs for diverse construction of complex N-heterocyclic structures has gained increasing attention. This synthetic strategy relies on the I 2 -mediated Strecker degradation, which introduces α-AAs as electrophilic carbon species into the domino reaction sequence via decarboxylation and deamination processes. In this review, we have summarized recent advances in this emerging area.

Defluorinative cyclization of CF 3 -alkenes has emerged as a reliable strategy for crafting intricate polycyclic frameworks. In this study, a facile defluorinative bicyclization approach was developed for the construction of 4 H ,5 H -pyrano[3,2- c ]chromenes under mild conditions involving a sequence of intramolecular cyclization and intermolecular defluoroheterocyclization. A variety of polysubstituted 4 H ,5 H -pyrano[3,2- c ]chromenes featuring C2-fluorine could be synthesized in good yields with excellent tolerance toward various functional groups. Moreover, the introduction of a C-F bond provides additional possibilities for further modification of this skeleton. The product features aggregation-induced emission (AIE) characteristics after simple modification, which is promising for chemical and biomedical imaging.

Natural product total synthesis has trailblazed in the era of multistep synthesis. The strategic application of existing synthetic methodologies and the stepwise construction that revolves around newly developed, tailored key steps, are two basic tactics in the principle of classic retrosynthetic analysis. However, a new synthetic model, termed self-organized total synthesis, has emerged in recent years, enabling the rapid creation of specific natural products by a one-pot reaction. Distinct from conventional analysis associated with certain bond disconnections, the design of self-organized total synthesis focuses on seeking a series of self-organized reaction sequences which can be integrated compatibly under a uniform condition, therefore allowing the entire sequence to proceed in one pot, and most importantly, starting from commercially available feedstocks or biomass materials. Whilst dauntingly challenging, this synthetic strategy is more consistent with the biogenetic pathway of natural products compared with conventional counterparts, and will hopefully provide the shortest synthesis for such natural products. Through this rational analysis, one-pot total synthesis is no longer in the way of serendipity but can be precisely designed and manipulated. In this review, we account for the definition, delimitation, and categorization of self-organized total synthesis and then elucidate a comprehensive understanding of this synthetic strategy based on our intensive explorations. We also highlight the contributions of other research groups in this growing field and anticipate that it will give rise to advancing new methodologies, as well as new concepts within organic synthesis.

A facile one-pot synthetic method has been developed for constructing 6- oxa -spiro[4.5]decane skeletons by merging the ring-opening of benzo[ c ]oxepines and formal 1,2-oxygen migration reactions. More than 30 examples of the 6- oxa -spiro[4.5]decane derivatives have been synthesized under transition-metal-free conditions.

A three-component annulation reaction and trifluoromethylation for the construction of 3-(trifluoromethyl)-4 H -pyrans using β-CF 3 -1,3-enynes, BrCF 2 CO 2 Et, and sulfoxonium ylides as readily available substrates has been developed. This metal-free process involves two C-F bond cleavages of β-CF 3 -1,3-enynes and a CF 3 group generated in situ from BrCF 2 CO 2 Et. This method is applicable to the late-stage modification of pharmaceutically active molecules.

In this work, a highly efficient rongalite/iodine-mediated oxime formation reaction for the preparation of thiohydroximic acids from methyl ketones by employing copper nitrate as the [NO] reagent has been developed. Notably, copper nitrate participated as both a catalyst and the mild oximation reagent in the transformation. This reaction is highly efficient and facile, with a broad substrate scope, especially for fused ring skeleton substrates, heterocyclic skeleton substrates, and acetyl-substituted natural products. Mechanistic studies revealed that copper nitrate might be converted into a NO 2 radical or the NO 2 radical dimeric forms as an ion-pair equivalent to participate in the transformation.

In this paper, novel sulfur-containing 1,6-dihydrofuro[3,2- b ]pyrazolo[3,4- e ][1,4]thiazine skeletons were constructed from the simple and readily available materials enaminone, 5-aminopyrazole, and 1,4-dithiane-2,5-diol. Furthermore, a novel 1,4-dithiane-2,5-diol reaction mode has been developed through a double-dipole-reversal process induced by iodine that results in the formation of six new bonds and two new rings in a one-pot reaction. This method shows good substrate compatibility, and the products can be further modified with a variety of pharmaceuticals. Additionally, this novel skeleton exhibits good fluorescence properties in solution, enabling bright and stable green fluorescence imaging in HeLa cells.

A cascade oxidation/Pictet-Spengler condensation/annulation process has been developed for the one-pot total synthesis of nitramarine, nitraridine, and their analogues. The procedure proceeded with easily available quinolines and tryptophan derivatives. A simple and metal-free approach, wide substrate scope, and functional group tolerance make it applicable for the synthesis of diverse bioactive nitramarine, nitraridine, and their derivatives. Furthermore, the bioactivity evaluation has identified two promising leading compounds 5d and 5e with potent antitumor proliferative activity against breast cancer cells.

An oxidant-controlled divergent synthesis of a pyrrolidone fused pyrimido[1,2- b ]indazole skeleton was developed through selective cyclization of an in situ generated enone intermediate and 1 H -indazol-3-amine. The one-pot, metal-free process formed three C-N bonds, one C-C bond, and a tetrasubstituted carbon stereocenter containing a hydroxyl group. This method not only allowed for the synthesis of over 60 new pyrrolidone fused pyrimido[1,2- b ]indazole derivatives, but was also compatible with the transformation of complex active molecules and the derivation of target products. Significantly, product 4q exhibited aggregation-induced emission (AIE) characteristics without any further modification.

A novel process using N -benzylhydroxylamine hydrochloride as a "C1N1 synthon" in [2+2+1] cyclization for the construction of 1,2,5-trisubstituted imidazoles has been described for the first time. The key to realizing this process lies in capturing arylamines by in situ generated novel acyl ketonitrone intermediates. Subsequent tautomerization activates the α-C(sp 3 )-H of N -benzylhydroxylamines, and thus breaks through its inherent reaction mode and achieves N , α-C site-selective cyclization. Furthermore, this method enables scale-up synthesis and late-stage modification of complex molecules.

An unconventional [1 + 1 + 1 + 1 + 1 + 1] annulation process was developed for the construction of β,β-dithioketones by merging C-C and C-S bond cleavage. In this reaction, rongalite concurrently served as triple C1 units, dual sulfur(II) synthons, and a reductant for the first time. Mechanism investigation indicated that the reaction involved the self-mediated valence state change of rongalite. By performing this step-economical method, the challenging construction of C 5 -substituted 1,3-dithiane can be achieved under mild and simple conditions.

An efficient synthetic method for constructing 2,3- and 2,4-disubstituted pyrimidio[1,2- b ]indazole skeletons through I 2 -DMSO-mediated and substrate-controlled regioselective [4 + 2] cyclization is reported. The reaction conditions are mild, its operation is simple, and the substrate scope is wide. More than 60 pyrimidio[1,2- b ]indazole derivatives have been synthesized, providing a new methodology for constructing related molecules and potentially enriching bioactive-molecule libraries.

A novel iodine-promoted difunctionalization of α-C sites in enaminones was demonstrated as a means of synthesizing a variety of fully substituted thiazoles by constructing C-C(CO), C-S, and C-N bonds. This transformation allows the realization of enaminones as unusual aryl C2 synthons and simultaneously allows the thioylation and dicarbonylation of α-C sites. A preliminary mechanistic study was performed and indicated that the cleavage of C═C bonds in enaminones involves a bicyclization/ring-opening and oxidative coupling sequence.

An iodine-mediated cyclization has been developed to 4-aryl- NH -1,2,3-triazoles, with p -toluenesulfonyl hydrazide and sulfamic acid used as nitrogen sources. Sulfamic acid plays a crucial role in this reaction by both acting as a substrate and providing an acidic environment. This reaction offers a metal- and azide-free strategy to access NH -1,2,3-triazoles.

Herein, we disclose a straightforward approach to access transition-metal-free reductive N -formylation of nitroarenes. This reaction integrates the dual role of rongalite, which acts as a reductant and a C1 building block concurrently. This provides an alternative method for the synthesis of N -aryl formamides from nitroarenes, including the construction of a C-N bond. The utility of this protocol was demonstrated by scale-up synthesis and late-stage functionalizations of complex molecules.

An I 2 -DMSO-mediated multicomponent [3+1+2] cascade annulation reaction using aryl methyl ketones, enaminones, and benzo[ d ]isoxazol-3-amine as substrates has been developed. This metal-free reaction involved the transannulation of benzo[ d ]isoxazol-3-amines with the formation of two C-N bonds and a C-C bond in one pot. Notably, a pyrimidine ring with a 1,4-dicarbonyl scaffold could efficiently transform into a pyrimido[4,5- d ]pyridazine skeleton. The phenolic hydroxyl group of the target product could undergo further modification with pharmaceuticals, demonstrating the utility of this method.

The precise aromatization of the C-ring of podophyllotoxone to access value-added dehydropodophyllotoxin derivatives conventionally requires the use of equivalent amounts of unsustainable oxidants and suffers from inefficiencies. Taking advantage of the hydridic character of the C8 and C8' of podophyllotoxone, we have developed an I 2 -DMSO catalytic manifold that enables a green and selective dehydrogenative aromatization to overcome these synthetic challenges. An unprecedented dehydrogenative amination of podophyllotoxone derivatives was also realized using aniline as the reaction partner.

A novel multicomponent cascade cyclization reaction in one pot for the preparation of pyrido[3,2- a ]phenoxazin-5-ones from simple o -aminophenols, paraformaldehyde, and enaminones has been established. It is noteworthy that o -aminophenol plays multiple roles serving as both a bis-nucleophile and an iminoquinone precursor, which can in situ generate aminophenoxazinones to undergo the Povarov reaction for the first time to yield pyrido[3,2- a ]phenoxazin-5-ones with a high efficiency. Moreover, the photoluminescence of pyrido[3,2- a ]phenoxazin-5-ones has polarity sensitivity and features aggregation-induced emission (AIE) characteristics, which is promising for bioimaging and theranostic applications.

Here, an efficient leaving group-activated methylene alcohol strategy for the preparation of primary propargyl alcohols from terminal alkynes by employing the bulk industrial product rongalite as the C1 unit has been described. The reaction avoids the low-temperature reaction conditions and inconvenient lithium reagents required for the classical method of preparing primary propargylic alcohols. Preliminary mechanistic studies showed that the reaction may not proceed via formaldehyde intermediates, but through the direct nucleophilic attack of the terminal alkyne on the carbon atom of rongalite by activation through SO 2 - as a leaving group.

2-Hydroxy-4-morpholin-2,5-diarylfuran-3(2 H )-one derivatives were constructed sequentially using iodine and zinc dust from simple and readily available methyl ketone and morpholine as the starting materials. Under mild conditions, C-C, C-N, and C-O bonds formed in a one-pot synthesis. A quaternary carbon center was successfully constructed, and the active drug fragment morpholine was introduced into the molecule.

A [3 + 1 + 2] cyclization-rearrangement reaction scheme was developed to synthesize pyrimido[1,2- b ]indazoles from aryl methyl ketones, 3-aminoindazoles, and gem -diarylethenes. This metal-free process proceeds via a sequential aza-Diels-Alder reaction and Wagner-Meerwein rearrangement, and a possible reaction mechanism was demonstrated based on control experiments. This method exhibits good substrate compatibility and allows simple reaction conditions. Moreover, the products display significant aggregation-induced emission characteristics after simple modifications.

A concise and efficient hydrodefluorination process was developed for the synthesis of gem -difluoroalkenes. This reaction employs rongalite as a masked proton source and does not require any additional catalysts or reductants. Notably, trifluoromethyl alkenes having both terminal and internal double bonds are compatible with this process, allowing for a wider range of substrates. The successful late-stage functionalizations of pharmaceuticals and gram-scale syntheses were used to demonstrate the viability of this method.

Concise synthesis of functionalized quinolines has received continuous research attention owing to the biological importance and synthetic potential of bicyclic N -heterocycles. However, synthetic routes to the 2,4-unsubstituted alkyl quinoline-3-carboxylate scaffold, which is an important motif in drug design, remain surprisingly limited, with modular protocols that proceed from readily available materials being even more so. We herein report an acidic I 2 -DMSO system that converts readily available aspartates and anilines into alkyl quinoline-3-carboxylate. This method can be extended to a straightforward synthesis of 3-arylquinolines by simply replacing the aspartates with phenylalanines. Mechanistic studies revealed that DMSO was activated by HI via a Pummerer reaction to provide the C1 synthon, while the amino acid catabolized to the C2 synthon through I 2 -mediated Strecker degradation. A formal [3 + 2 + 1] annulation of these two concurrently generated synthons with aniline was responsible for the selective formation of the quinoline core. The synthetic utility of this protocol was illustrated by the efficient synthesis of human 5-HT4 receptor ligand. Moreover, an unprecedented chemoselective synthesis of 2-deuterated, 3-substituted quinoline, featuring this reaction, has been established.

We herein report an efficient synthesis of 2-aroyl-3-arylquinolines from phenylalanines and anilines. The mechanism involves I 2 -mediated Strecker degradation enabled catabolism and reconstruction of amino acids and a cascade aniline-assisted annulation. Both DMSO and water act as oxygen sources in this convenient protocol.

A transition-metal-free formal (4 + 2) cycloaddition for the direct assembly of acridone derivatives has been developed from simple and easily accessible o -aminobenzamides and 2-(trimethylsilyl)aryl triflates. The base played an important role in the selective controlled synthesis of N -H and N -aryl acridones. A preliminary study on the fluorescence properties of N -aryl acridones demonstrated that they could be used as fluorescent materials with a broad emission range.

An I 2 -DMSO mediated multicomponent [3+2] cascade annulation reaction using methyl ketones, 1,2,3,4-tetrahydroisoquinolines (THIQ) and cyclopropenones as readily available substrates has been developed. This metal-free process involves N-H/α-C(sp 3 )-H trifunctionalization of THIQ and C-C bond cleavage of cyclopropenone, providing a direct approach to obtain pyrrolo[2,1- a ]isoquinoline derivatives with a quaternary carbon center. Two C-C bonds and one C-N bond are formed efficiently in one pot.

An efficient I 2 -promoted one-pot one-step three-component reaction for the synthesis of sulfhydryl indolizines from methyl ketones, 2-pyridylacetate derivatives, and sulfonyl hydrazides via an in situ cyclization-rethiolation strategy has been developed. This protocol shows excellent substrate compatibility, including for chain and cyclic aliphatic methyl ketones, natural product pregnenolone acetate, and phosphorus-containing methyl ketones, affording a series of valuable aliphatic-substituted indolizines in good yields.

Precise control of the chemoselectivity of the halogenation of a substrate equipped with multiple nucleophilic sites is highly demanding and challenging. Most reported chlorinations of methyl ketones show poor compatibility or even exclusive selectivity toward electron-rich arene, olefin, and alkyne residues. This is attributed to the direct or in situ employment of electrophilic Cl 2 /Cl + species. Here, we reported that, even bearing those competitive residues, methyl ketones can still undergo dichlorination to afford α,α-dichloroketones in a chemo-specific manner. Enabled by the I 2 -dimethyl sulfoxide catalytic system, in which hydrochloric acid only acts as a nucleophilic Cl - donor, this straightforward dichlorination reaction is safe and operator-friendly and has high atomic economy, giving access to structurally diverse α,α-dichloroketones in good yields and with good functional-group tolerance.

A reductive coupling reaction was established for the synthesis of diaryl 1,2-dicarbonyl compounds from aryl methyl ketones in good yields. The mechanistic study showed the reaction undergoes C(CO)-C(sp 3 ) bond cleavage, with the reductive coupling reaction occurring through an electron transfer process. Notably, the reaction not only is simple to operate but also has mild reaction conditions and a wide range of applicable substrates.

An unprecedented [1+1+1+1+1+1] annulation process has been developed for the construction of tetrahydro-2 H -thiopyran 1,1-dioxides. Notably, rongalite acted as a tethered C-S synthon in this reaction and can be chemoselectively used as triple C1 units and as a source of sulfone. Mechanistic investigation indicated that two different carbon-increasing models are involved in this reaction in which rongalite serves as C1 units.

A cascade 6-endo-dig cyclization reaction was developed for the switchable synthesis of halogen and non-halogen-functionalized pyrazolo[3,4- b ]pyridines from 5-aminopyrazoles and alkynyl aldehydes via C≡C bond activation with silver, iodine, or NBS. In addition to its wide substrate scope, the reaction showed good functional group tolerance as well as excellent regional selectivity. This new protocol manipulated three natural products, and the arylation, alkynylation, alkenylation, and selenization of iodine-functionalized products. These reactions demonstrated the potential applications of this new method.

A high efficiency protocol was developed for the synthesis of 2,5-disubstituted oxazoles via iodine-promoted oxidative domino cyclization. These reactions were performed with readily available methyl azaarenes and α-amino ketones under metal-free conditions. This protocol is a simple method with high functional group compatibility, a wide range of substrates, and excellent yield, providing a new way to synthesize azaarene-attached oxazoles.

Pd-catalyzed cascade hydroarylation and C-H germylation of nonterminal alkenes and aryl iodides enabled by hydroxyl assistance have been developed. The key step in this C-H germylation cascade is the formation of a highly reactive oxo-palladacycle intermediate, which markedly restrained the β-H elimination process. Mechanistically, control experiments indicated that the hydroxyl group played an important role in this process. This transformation shows excellent reactivity and selectivity for most substrates investigated.

A novel multicomponent cascade cyclization and sulfenylation/selenation using aryl methyl ketones, isoquinolin-1-amine, and sodium arylsulfinates/1,2-diphenyldiselane to synthesize imidazo[2,1- a ]isoquinoline derivatives in one-pot via the construction of two C-N bonds and one C-S/C-Se bond has been reported. This multicomponent reaction realizes simultaneous C(sp 3 )-H amination and sulfenylation/selenation, avoiding complicated prior substrate preparation. This process has simple operating conditions and good substrate compatibility.

An I 2 -DMSO-mediated cascade reaction using methyl ketones and 1,2,3,4-tetrahydroisoquinolines (THIQs) as commercially available substrates has been developed for the construction of pyrrolo[2,1- a ]isoquinoline derivatives. This metal-free process involves N-H/α-C(sp 3 )-H difunctionalization of THIQ. Two C-C bonds and one C-N bond are formed in one pot under mild conditions. Besides, a quaternary carbon center has been constructed in this transformation efficiently.

An iodine-catalyzed methyl azaarene sp 3 C-H functionalization has been developed for the synthesis of a seven-membered O -heterocyclic architecture containing three different heterocyclic aromatic hydrocarbons. This method can be applied to a wide range of substituted methyl azaarenes and diverse 2,4-dihydro-3 H -pyrazol-3-ones, and brings about the efficient preparation of 2,9-dihydrooxepino[2,3- c :6,5- c ']dipyrazol-3(7 H )-ones in high yields with the merits of low catalyst loading, good functional group tolerance and metal-free conditions.

Rongalite has been used in several challenging synthetic transformations with operationally simple and effective protocols. However, the employment of multiple characteristics of rongalite in synthetic chemistry is comparatively little known. Herein we report a separate-embedding type sulfonylmethylation of sulfoxonium ylides in which rongalite concurrently acted as a sulfone source, C1 synthon, radical initiator, and potential reducing reagent for the first time. Notably, this facile and easy-handling reaction does not require a catalyst or prefunctionalized sulfonylmethylation reagents.

We herein report an I 2 /CuCl 2 -copromoted diamination of C(sp 3 )-H bonds for the preparation of 2-acyl-4-aminoquinazolines from methyl ketones, 2-aminobenzonitriles, and ammonium acetate. This reaction features operational simplicity, commercially available substrates, mild reaction conditions, and good functional group compatibility. Mechanistic studies indicate that CuCl 2 plays a pivotal role in this transformation. This study uses a methyl group as a novel input to construct 2-acyl-4-aminoquinazoline derivatives for the first time.

A copper-catalyzed oxidative C(sp 3 )-H/C(sp 3 )-H cross-coupling reaction of methyl ketones and 3-methylbenzo[ c ]isoxazoles has been developed for the direct synthesis of 3-oxoindolin-2-ylidene derivatives. This process involves an intermolecular nucleophilic addition/ring-opening/aza-Michael addition cascade, providing indigoid analogues with high atom economy and as single isomers exclusively under mild conditions.

An iodine-promoted one-pot cascade oxidative annulation reaction has been developed for the synthesis of chromone-fused-pyrrolo[2,1- a ]isoquinolines and indolizino[8,7- b ]indoles from o -acetylphenoxyacrylates, tetrahydroisoquinolines, and noreleagnines. This process underwent a logical approach to both chromone-fused-pyrrolo[2,1- a ]isoquinolines and chromone-fused-indolizino[8,7- b ]indoles isolamellarin derivatives. Manipulations of l-menthol and dl-α-tocopherol demonstrate the applications of this strategy.

We herein report an iodine-mediated formal [2 + 2 + 1] cyclization of methyl ketones, p -toluenesulfonyl hydrazines, and 1-aminopyridinium iodide for preparation of 4-aryl- NH -1,2,3-triazoles under metal- and azide-free conditions. Notably, this is achieved using p -toluenesulfonyl hydrazines and 1-aminopyridinium iodide as azide surrogates, providing a novel route to NH -1,2,3-triazoles. Furthermore, this approach provides rapid and practical access to potent inhibitors of indoleamine 2,3-dioxygenase (IDO).

A novel iodine promoted cyclization of enaminone with aryl methyl ketones has been developed as a straightforward method for constructing 2-hydroxy-pyrrol-3(2 H )-ones. This strategy affords structurally diverse 2-hydroxy-pyrrol-3(2 H )-ones rings in high yields. Moreover, a quarternary alcohol has been constructed efficiently in the reaction. Product purification required only washing with CH 2 Cl 2 solvent, thereby avoiding traditional chromatography and recrystallization, making this an example of group-assisted purification chemistry.

A novel [2 + 1 + 3] cyclization reaction for the synthesis of 2-aryl-4-quinolinecarboxylates from aryl methyl ketones, arylamines, and 1,3-dicarbonyl compounds has been established. This metal-free process achieved the C-C bond cleavage of 1,3-dicarbonyl compounds directly as a single-carbon synthon. The reaction is highly efficient and has good substrate compatibility while operating under mild conditions. This method has good practicability and successfully realized the synthesis of bioactive molecules.

A novel I 2 -mediated Povarov reaction of arylacetylenes and anilines for the synthesis of 2,4-substituted quinolines has been developed, in which arylacetylene first acts as both a diene precursor and dienophile. This work further develops the Povarov reaction to expand the types of diene precursors. Preliminary mechanistic studies indicate that the I 2 /DMSO system realized the oxidative carbonylation of C(sp)-H of arylacetylene and then undergoes a [4 + 2] cycloaddition reaction.

Quinazoline skeletons are synthesized by amino acid catabolism/reconstruction combined with the insertion/cyclization of dimethyl sulfoxide for the first time. The amino acid acts as a carbon and nitrogen source through HI-mediated catabolism and is then reconstructed using aromatic amines and dimethyl sulfoxide (DMSO) as a one-carbon synthon. This protocol is of great significance for the further study of the conversion of amino acids.

An I 2 -DMSO mediated oxidative amidation of methyl ketones using anthranils as masked N-nucleophiles has been developed for the direct synthesis of α-ketoamides with high atom-economy. This metal-free process involves reductive N-O bond cleavage of anthranils and oxidative C-N bond formation of methyl ketones under mild conditions. The iodo group and electrophilic formyl group provide multiple possibilities for further functionalization of α-ketoamides.