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Synthesis of the C19-truncated maltepolide E has been accomplished via a diene–ene RCM strategy without damage to the C11–C14 alkenyl epoxy unit. Upon release of the C17-OH group, it attacked at the C14 position with double bond migration and epoxide ring-opening to furnish the C19-truncated maltepolide A and B as proposed for the biosynthesis of maltepolides. Preliminary cytotoxicity data of the synthesized C19-truncated maltepolides against L929 mouse fibroblast cell line suggest irrelevance of the vinyl epoxide and importance of the conjugated dienyl keto unit for the observed anticancer activity.

An I

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.

An unprecedented I2/FeCl3-promoted cascade reaction of aryl methyl ketones with 8-aminoquinolines for the convenient synthesis of (E)-3-(2-acyl-1H-benzo[d]imidazol-4-yl)acrylaldehydes was developed by merging annulation with ring deconstruction. This novel strategy unlocked the new reactivity of 8-aminoquinolines and provided an attractive platform for the ring opening of unactivated N-heteroaromatic compounds. Preliminary mechanistic investigation suggested that dual C(sp3)-H amination/C-N bond cleavage were key reaction steps. Furthermore, late-stage modification of the obtained products successfully delivered pyrazole and isoxazole derivatives, increasing the practicability and application potential of this methodology in organic synthesis.

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.

A novel and efficient formal [4 + 2+1] annulation of aryl methyl ketones and 2-aminobenzyl alcohols for the synthesis of benzo[e][1,4]diazepin-3-ones is reported. This reaction successfully affords diverse seven-membered ring lactams via dual C-O bond cleavage. A preliminary mechanistic study showed that a multicomponent dicyclization and ring-opening sequence might occur, with the introduction of methyl sulfide proposed as the last step. This efficient strategy with mild reaction conditions and a broad substrate scope has potential applications in chemistry and medicine.

A N–H/α,β-C(sp3)-trifunctionalization of l-proline, proceeding through an iodine-promoted consecutive decarboxylation/ring-opening/dicyclization process, is achieved. This strategy affords structurally diverse fused N-heterocycles in good yields with a wide substrate scope. Preliminary mechanistic studies indicate that catabolism of l-proline might be involved in this cascade reaction and the in situ generated intermediate 4-aminobutanal was identified as the key intermediate. Notably, this domino strategy enriches the reactivity of versatile l-proline in the synthesis of fused heterocycles.

The first synthesis of 2,3-diaroyl quinolines via a formal [3 + 2 + 1] cycloaddition of enaminones, aryl methyl ketones, and aryl amines is disclosed. This reaction efficiently affords a 1,4-dicarbonyl scaffold, which is a useful building block for constructing complex fused heterocycles. Furthermore, the 1,4-dicarbonyl scaffold has been used directly to prepare pyridazino[4,5-b]quinoline skeletons in one-pot.

An unprecedented I

A novel and efficient multicomponent cyclization of methyl ketones, cyanamides, and arylamines for the synthesizing 2,4-diamino-1,3,5-triazines via consecutive formation of four C-N bonds is reported. This multicomponent reaction is characterized by the employment of two molecules of cyanamide for double C(sp3)-H amination of methyl ketones, avoiding complicated prepreparation of substrates and expanding the substrate scope. Furthermore, this multicomponent cyclization strategy provides a new approach for generating diverse 2,4-diamino-1,3,5-triazines with a broad substrate scope under mild conditions.

The first synthesis of arylquinazolinones has been disclosed via the consecutive oxidative cyclization/ring-opening of anilines and methyl ketones. This transformation is characterized by the splitting of the methyl ketone as acyl and C1 sources through C(CO)-C(sp

We report an I2/FeCl3-co-promoted formal [2 + 2+1] annulation of aryl methyl ketones, 2-aminobenzyl alcohols, and p-toluenesulfonylmethyl isocyanide (TosMIC) by neighboring group (-CH2OH) assistance. This is a novel example of using the Van Leusen reagent as a unique C1N1 "two-atom synthon" in the synthesis of imidazoles. Preliminary mechanism studies showed that TsCH2NH2 might be the key intermediate in this reaction. Furthermore, this reaction not only unlocks a novel strategy for imidazole synthesis, but also exploits a new reactivity of TosMIC.

A highly efficient rongalite-mediated three-component radical annulation reaction to furnish fully substituted pyrazoles from aryldiazonium salts and α,β-unsaturated aldehydes or ketones under metal- and oxidant-free conditions at room temperature has been developed. In this transformation, aryldiazonium salts served as the precursor of both the aryl and aryl hydrazine units. Mechanistic investigations indicated that rongalite could act as a radical initiator and reducing reagent simultaneously in the reaction.

An efficient and practical de novo synthesis of pyrrole-2-carbaldehyde skeletons featuring oxidative annulation and Csp3–H to C═O oxidation is presented, exemplified by the preparation of pyrrole-2-carbaldehyde derivatives from aryl methyl ketones, arylamines, and acetoacetate esters. Preliminary mechanistic investigations indicate that the aldehyde oxygen atom originates from oxygen. Moreover, the developed scalable approach provides a distinct advantage over traditional oxidative functionalization of C–H moieties, avoiding the use of stoichiometric quantities of hazardous oxidants.

A synergistic I2/amine promoted formal [4 + 2] cycloaddition of methyl ketones, arylamines, and aryl(alkyl)acetaldehydes as alkene surrogates has been established. This protocol allowed the modular synthesis of various 2-acyl-3-aryl(alkyl)quinolines, rather than 2,4-substituted quinolines. Notably, the arylamines not only participated as reactants in this reaction but also acted as indispensable catalysts to promote enamine formation. Moreover, mechanistic investigation suggested that the reaction occurred via an iodination/Kornblum oxidation/Povarov/aromatization sequence.

A novel iodine-promoted oxidative cross-coupling/cyclization of 2-(pyridin-2-yl)acetate derivatives and methyl ketones via the cleavage of multiple Csp3–H bonds has been developed, which also achieved efficient cleavage of a C–C bond in the 2-(pyridin-2-yl)acetate derivatives. This protocol represents an elegant molecular fragment assembly of diverse 3-(pyridin-2-yl)indolizines via a formal [3 + 1 + 1] annulation. Notably, the pyridine derivatives serve two pivotal roles to provide two fragments to construct 3-(pyridin-2-yl)indolizine skeletons, rather than the single role in building common indolizines.

A highly efficient I2-promoted formal [4 + 2] cycloaddition has been developed for the synthesis of 2-acylquinolines from methyl ketones and arylamines using 1,4-dithane-2,5-diol as an ethylene surrogate. Moreover, the investigation of the mechanism suggested that this reaction occurred via an iodination/Kornblum oxidation/Povarov/aromatization sequence. It is noteworthy that the arylamine substrate also played an important role in promoting the reaction.

An I2-promoted domino bicyclization approach via multiple sequential C–H functionalization was serendipitously discovered for the synthesis of 1,2-fused oxindoles from methyl ketones and anilines. This approach was optimized, resulting in a concise and atom-economical approach for the one-pot construction of 1,2-fused oxindoles from methyl ketones and anilines rather than using preexisting indolin-3-ones or indoles. Mechanistic studies revealed that the key step involved an oxidative cross-coupling between in situ generated phenylglyoxal and α,α-diaminoketone.

A novel and efficient formal [4 + 2+1] annulation of aryl methyl ketones and 2-aminobenzyl alcohols for the synthesis of benzo[

A N-H/α,β-C(sp

The first synthesis of 2,3-diaroyl quinolines via a formal [3 + 2 + 1] cycloaddition of enaminones, aryl methyl ketones, and aryl amines is disclosed. This reaction efficiently affords a 1,4-dicarbonyl scaffold, which is a useful building block for constructing complex fused heterocycles. Furthermore, the 1,4-dicarbonyl scaffold has been used directly to prepare pyridazino[4,5- b]quinoline skeletons in one-pot.

The one-pot total synthesis of evodiamine and its analogues is achieved using a three-component reaction. Through continuous biscyclization, various readily available substrates with good functional group tolerance were easily incorporated into biologically active quinazolinocarboline backbones. The use of triethoxymethane as a cosolvent was crucial for this quick and straightforward transformation.