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A silver‐catalyzed protocol for [3+1+1] annulation of nitrones and isocyanoacetates is reported. The reaction is proposed to proceed through sequential [3+2] cycloaddition, ring‐opening, cyclization‐oxidation, and dealkylation, allowing access to a broad scope of valuable polysubstituted imidazoles in high yields. [ABSTRACT FROM AUTHOR]

A protocol involving cooperative silver‐ and base‐catalyzed diastereoselective cycloaddition of nitrones with isocyanides is described, providing access to a wide range of 2‐imidazolinone derivatives with various functional groups as single diastereomers. Varying the base and temperature of the reaction allowed selective access to both diastereomers of the product. A plausible reaction mechanism is proposed and supported by DFT calculations. [ABSTRACT FROM AUTHOR]

A variety of functionalized 2‐pyrrolidinones bearing N‐trifluoromethylphenyl moieties were prepared in moderate to good yields with high diastereoselectivity through copper(II)‐catalyst and base co‐catalyzed formal [4+1] cycloaddition of cinnamaldehyde nitrones with 1‐ethynylnaphthalen‐2‐ols in the presence of m‐CPBA as the oxidant. The triple bond of 1‐ethynylnaphthalen‐2‐ol served as one‐carbon synthon for the pyrrolidinone ring formation. Mechanistic studies revealed that m‐CPBA played an important role to interrupt the intramolecular O‐cyclization to afford the 2‐pyrrolidinones. Moreover, the reaction could be easily performed at gram scales and the obtained products were selectively converted into diverse pyrroline scaffolds. [ABSTRACT FROM AUTHOR]

The organocatalytic asymmetric synthesis of hexahydropyridazines were performed through a unique Michael/amination/cyclization reaction. The organocascade reaction proceeded smoothly between 2-arylidene-1,3-indandiones and aldehydes followed by the addition of azodicarboxylates catalyzed by the privileged organocatalyst α,-α-L-diphenylprolinol trimethylsilyl ether (10 mol%) in the presence of a base additive Et3N (20 mo%) at 0 °C. A series of substituted hexahydropyridazines were obtained in good to high chemical yields (55-78 %) and reasonable to high levels of stereoselectivities (51-93 % ee and 4 : 1 d.r.). [ABSTRACT FROM AUTHOR]

An abstract of the article "KOt-Bu/DMF Promoted Intramolecular Cyclization of 1,1'-Biphenyl Aldehydes and Ketones: An Efficient Synthesis of Phenanthrenes" by Y.-Y. Chen and colleagues is presented.

It is suggested, that a DMSO radical generated in tBuOK/DMSO systems works as the crucial initiator for the title cyclization process. [ABSTRACT FROM AUTHOR]

The 6-endo-cyclization of substrates (VI) and (VIII) gives rise to corresponding tetrahydroquinoline derivatives, whilst the reaction of substrate (XI) leads to indoline (XII) as a result of a 5-exo-cyclization. [ABSTRACT FROM AUTHOR]

A simple and efficient visible‐light‐promoted selenylation/cyclization of enaminones have been realized for the practical synthesis of 3‐selanyl‐4H‐chromen‐4‐ones. This reaction is performed in the mild conditions, no transition metal catalyst or photocatalysts and no additional oxidants are required. In addition, the 3‐selanyl‐4H‐chromen‐4‐ones could be easily converted to selanyl‐functionalized pyrimidines by reacting with benzamidine substrates. [ABSTRACT FROM AUTHOR]

A practical method for the synthesis of selenylsubstituted indolo[2,1‐a]isoquinolin‐6(5H)‐ones through Fe(OTf)3‐promoted tandem selenylation/cyclization of 2‐arylindoles was developed. In this transformation, new C−Se bond and C−C bond were constructed simultaneously under mild conditions. [ABSTRACT FROM AUTHOR]

The scalable reaction of substituted N-phenoxyacetamides with 3-aryl, hetaryl, and alkyl substituted propargyl carbonates furnishes 3-alkylidene dihydrobenzofuran derivatives in moderate to high yields. [ABSTRACT FROM AUTHOR]

A novel method for a hydride-induced anionic ring-closure is used to synthesize phenanthridines. [ABSTRACT FROM AUTHOR]

A diagram which shows the synthesis of the chemical compound tetrahydropyrroles based on spiropyrazolone through three-component 1,3-dipolar cycloadditions is presented.

In most cases, the title reaction yields the expected products under the mild conditions A). [ABSTRACT FROM AUTHOR]