PPh₃ Mediated Reductive Annulation Reaction between Isatins and Electron Deficient Dienes to Construct Spirooxindole Compounds

A PPh₃ mediated reductive annulation reaction between isatins and 4,4-dicyano-2-methylenebut-3-enoates was developed. The reaction provided an alternative method for constructing five- and three-membered all-carbon spirooxindole compounds. Lithium chloride as a Lewis acid played a key role in the synthesis of spirocyclopentenyl oxindole compounds

PPh₃O as an Activating Reagent for One-Pot Stereoselective Syntheses of Di- and Polybrominated Esters from Simple Aldehydes

An efficient one-pot method for the syntheses of di- and polybrominated esters from readily available aldehydes is reported. The direct use of the <i>in situ</i> generated byproduct PPh₃O in the following reactions greatly improves the efficiency of the cascade. Also, the substrate scope of the reaction is proved to be broad

Direct Decarboxylative–Decarbonylative Alkylation of α‑Oxo Acids with Electrophilic Olefins via Visible-Light Photoredox Catalysis

The decarbonylation of primary, secondary, and tertiary alkyl-substituted acyl radicals has been investigated through photoredox catalysis. A series of quaternary carbons and γ-ketoesters have been directly constructed by the photoredox 1,4-conjugate addition of the corresponding alkyl ketoacids with electrophilic alkenes. And, the tertiary alkyl ketoacids have proved to be good precursors of tertiary alkyl radicals

Enantioselective Amine-Catalyzed [4 + 2] Annulations of Allene Ketones and 2,3-Dioxopyrrolidine Derivatives: Synthesis of 4<i>H</i>‑Pyran Derivatives

An efficient cinchona alkaloid-derived amine catalyzed asymmetric [4 + 2] cycloaddition is successfully developed. 4<i>H</i>-Pyran fused pyrrolin-2-one products are readily obtained in moderate to high yields with good enantioselectivites by employing allene ketones and 2,3-dioxopyrrolidine derivatives as substrates