Decarboxylative Organocatalyzed Aldol-Type Addition Reaction of Chloroacetate Surrogates.

Chlorinated malonic acid half thioesters were established as chloroacetate surrogates and used in stereoselective organocatalyzed decarboxylative aldol-type additions. Enantioenriched α-chloro-β-hydroxy thioesters were obtained under mild reaction conditions in high yields and allowed for diverse derivatization as highlighted by the synthesis of (+)-prebalamide and (+)-norbalasubramide analogs.

Decarboxylative Organocatalyzed Addition Reactions of Fluoroacetate Surrogates for the Synthesis of Fluorinated Oxindoles.

Fluorinated malonic acid half thioesters (F-MAHTs) were used as thioester enolate equivalents in organocatalyzed addition reactions to isatins. The products from a range of different -protected and nonprotected isatins were obtained under mild reaction conditions in high yields and enantioselectivities. The unique reactivity of the thioester moiety enabled diverse derivatization and allowed for the straightforward access to a fluorinated analogue of the anticancer agent ()-YK-4-279, a therapeutically active compound against Ewing's sarcoma.

N-Heterocycle-Fused Pentalenes by a Gold-Catalyzed Annulation of Diethynyl-Quinoxalines and -Phenazines.

The gold-catalyzed annulation of diethynyl N-heterocycles for the synthesis of quinoxaline-/phenazine-based pentalenes and the study of their optoelectronic properties are described. The inhibition of the gold catalyst by the nitrogen centers in the substrate and the product could be overcome by increasing the reaction temperature to 130 °C, which usually leads to catalyst decomposition in gold catalysis. At 130 °C, 6,7-di(arylethynyl)quinoxalines in chlorobenzene give the corresponding pentalenes.