RESUMEN
A cooperative gold(I)/DMAP system catalyzes the (2 + 3) cycloadditions of yne-enones with oxindole-derived Morita-Baylis-Hillman (MBH) carbonates, yielding diverse bispiro-cyclopentene oxindole products. The mild, scalable protocol demonstrates broad substrate scope and excellent chemo- and diastereoselectivity. Mechanistic study reveals pivotal roles of both catalysts in the unique (2 + 3) cycloaddition. This strategy showcases superiority in achieving transformation with unique chemoselectivity and excellent diastereoselectivity, unattainable through traditional monocatalytic methodologies.
RESUMEN
Despite the widespread presence of the chiral cyclopentane motif, the asymmetric synthesis of cyclopentanes containing five stereocenters remains a formidable challenge. Here, we present an N-heterocyclic carbene (NHC)-catalyzed cascade reaction of enal and oxindole-dienone, which allows access to spiroxindole cyclopentanes featuring a complete set of chiral centers on the five-membered carbocycle. This strategy, characterized by the formation of multiple bonds and chiral centers, demonstrates a broad substrate scope, exclusive diastereoselectivity, and up to 99:1 er.
RESUMEN
In this study, we report an organocatalytic formal coupling strategy for aryl-naphthoquinones with thiosugars that provides straightforward access to the axially chiral naphthoquinone thioglycoside with excellent stereoselectivity. Mechanistic studies revealed the key role of H-bonding in stereochemical recognition. The reaction pathway involves the atroposelective addition, followed by stereoretentive oxidation of the hydroquinone intermediate.
Asunto(s)
Naftoquinonas , Tioglicósidos , TioazúcaresRESUMEN
A cross-coupling strategy of palladium-catalyzed ortho-C-H bond activation and intramolecular addition of N-C annulation to synthesize isoquinolin-1(2H)-ones has been developed. A wide range of α-bromo ketones with different substituents proceeded smoothly in this reaction, and varieties of isoquinolin-1(2H)-one derivatives were obtained in moderate to good yields.