Palladium-catalyzed decarboxylative α-allylation of thiazolidinones and azlactones with sulfonamido-substituted acyclic allylic carbonates

Abstract

A palladium-catalyzed decarboxylative α-allylation via aza-π-allylpalladium zwitterionic intermediates, is developed for the synthesis of 5-alkylated thiazolidinones and 2-piperidones.

Palladium-Catalyzed Cycloaddition Reactions of π–Allylpalladium 1,4-Dipoles with 1,3,5-Triazinanes: Access to Hexahydropyrimidines, 1,3-Oxazinanes, and 1,5-Diazocanes

“…Despite the successful construction of heterocyclic compounds through the cyclization reaction of 1,3,5-triazinanes with π-allylpalladium 1,3-dipoles , and the wide application of π-allylpalladium 1,4-dipoles in the efficient synthesis of heterocyclic compounds through cyclization reactions, the [4 + 2] cycloaddition reaction of π-allylpalladium 1,4-dipole precursors with 1,3,5-triazinane has not yet been achieved. To the best of our knowledge, the 5-methylene-1,3-oxazinan-2-ones could be used for the generation of aza-π-allylpalladium 1,4-dipole species, thereby undergoing allylic alkylation with diverse nucleophiles and further cyclization for the construction of nitrogen-containing heterocycles. , Inspired by these pioneering reports, and in continuation of our ongoing research interest in palladium-catalyzed decarboxylation for in situ formation of π-allylpalladium dipole intermediates and used in various cyclization, recently, we have developed a palladium-catalyzed decarboxylation of 5-methylene-1,3-oxazinan-2-ones to generate highly active aza-π-allylpalladium 1,4-dipoles, which could react with 1,3,5-triazinanes via [4 + 2] cycloaddition to access hexahydropyrimidines and undergo dimeric [4 + 4] cycloaddition for the construction of 1,5-diazocanes (Scheme , bottom). Nevertheless, the same catalytic system was also extended to acyclic sulfonamido-substituted allylic carbonates as aza-π-allylpalladium 1,4-dipole precursors for synthesizing hexahydropyrimidines.…”