Synthesis of Polysubstituted 2H -Pyran-2-ones or Phenols via One-Pot Reaction of (E )-β -Chlorovinyl Ketones and Electron-Withdrawing Group Substituted Acetates or β -Diketones

Pd-catalyzed domino Heck cyclization/cross-coupling of indoles with β-chlorovinyl ketones: synthesis of furan-bearing indolo[2,1-α]isoquinolines with antifungal activity

Herein, a palladium-catalyzed cross-coupling cascade cyclization of alkene-tethered indoles and (E)-β-chlorovinyl ketones, providing access to various furan-bearing indolo[2,1-α]isoquinolines, is reported. The reaction enables the rapid construction of one C-O bond and two C-C bonds to form bis-heterocycles. Furthermore, these furan-bearing indolo[2,1-α]isoquinolines exhibited certain antifungal activity in vitro. Notably, bis-heterocycles 3da (EC50 = 16.5014 μg mL-1) against Botryosphaeria dothidea and 3ar (EC50 = 18.2751 μg mL-1) against Rhizoctonia solani were identified to have good inhibitory effects.

Accessing Furan-Linked Methylene Oxindoles/Benzofurans via Stereoselective Palladium-Catalyzed Domino Cyclization/Cycloisomerization

A palladium-catalyzed domino cyclization/cycloisomerization reaction of alkyne-tethered carbamoyl chlorides with (E)-β-chloroenones is reported. This reaction proceeds via a syn-carbopalladation of the alkyne, followed by a vinyl-PdII-catalyzed cycloisomerization of the (E)-β-chloroenone cascade, which provides an efficient method to synthesize furan-linked methylene oxindoles. The reaction features stereodefined vinyl-PdII species, high to excellent 5-exo/6-endo selectivity, excellent Z/E selectivity, and the sequential formation of three bonds and bis-heterocycles. The strategy for the synthesis of furan-containing benzofurans has also been demonstrated.

Palladium-Catalyzed Domino Heck/Cross-Coupling Cyclization Reaction: Diastereoselective Synthesis of Furan-Containing Indolines

Herein, a palladium-catalyzed diastereoselective dearomatization/cross-coupling cyclization reaction between N-arylacyl indoles and (E)-β-chlorovinyl ketones is reported. Through this cyclization/cycloisomerization cascade, a series of furan-containing indolines were obtained in yields up to 95%. The reaction features readily accessible starting materials, benzyl Pd(II)-catalyzed cycloisomerization of (E)-β-chlorovinyl ketones, the sequential formation of three bonds and bis-heterocycles, and excellent diastereoselectivity. More importantly, the carbene-secondary benzyl migratory insertion is proven to be a critical process in the sequential cyclizations.