Palladium-Catalyzed Aryl-Furanylation of Alkenes: Synthesis of Benzofuran-Containing 3,3-Disubstituted Oxindoles

Abstract

A novel palladium-catalyzed aryl-furanylation of alkenes is described. This protocol provided a straightforward route to the synthesis of various benzofuran-containing 3,3-disubstitutedoxindole derivatives bearing a quarternary carbon center. In the cascade process, one C­(sp2)–O bond, two C­(sp2)–C­(sp3) bonds, an oxindole, and a furan ring are formed in a single chemical operation.

Recent Advances in the Synthesis of Five‐membered Nitrogen Heterocycles Induced by Palladium Ions and Complexes

“…Chen et al . have elaborated a novel palladium‐catalyzed aryl‐furanylation process leading to various benzofuran‐containing disubstituted oxindoles bearing a quaternary carbon atom [128] . The reaction of compounds 26 a and ethynylphenols gave products in low to excellent yields (Scheme 102).…”

“…Chen et al have elaborated a novel palladium-catalyzed aryl-furanylation process leading to various benzofuran-containing disubstituted oxindoles bearing a quaternary carbon atom. [128] The reaction of compounds 26 a and ethynylphenols gave products in low to excellent yields (Scheme 102). In this efficient cascade method intramolecular Heck cyclization, ments, int-58 formed in the last step was suggested to deliver the bicyclic derivatives.…”

Divergent reactivity of acrylamides and β-chloroenones under base-controlled palladium catalysis: construction of spirooxindoles and furan-containing 3,3-disubstituted oxindoles

“…1 Among the various catalytic cascades involving palladium intermediates, the transient σ-alkylpalladium( ii ) species generated from the carbopalladation of a double bond in Heck cyclization has remained a central topic, and it can be utilized as an active intermediate for further functionalization. 2 To date, several representative pathways involving σ-alkylpalladium intermediates have emerged: (1) they can be trapped with a variety of nucleophiles (Scheme 1a); 3 (2) they can coordinate the unsaturated bond and promote the second cyclization via nucleopalladation (Scheme 1b); 4 and (3) they can functionalize the unreactive remote C–H bond to generate spirocyclic palladacycle intermediates, which could undergo direct reductive elimination or further cross-couple with alkyl and aryl halides, diaziridinones, α-diazocarbonyl compounds, and disilanes to form diverse spiro-heterocyclic scaffolds. 5 More importantly, spirocyclic palladacycle intermediates can also be cross-coupled with π-systems such as arynes, 6 a , b alkynes, 6 c and oxabicycles 6 d via migratory insertion to afford interesting hetero-spirocycles, demonstrating the versatility of the palladium-catalyzed remote C–H functionalization (Scheme 1c).…”

Cobalt-promoted synthesis of sulfurated oxindoles via radical annulation of N-arylacrylamides with disulfides

“…4 Owing to their importance and versatility, the practical synthesis of functionalized 3,3-disubstituted oxindoles is of great importance and has received a considerable amount of attention in recent years. 5…”