One-pot furan synthesis through diethylzinc-mediated coupling reaction between two α-bromocarbonyl compounds.

Polysubstituted furans were synthesized in one-pot through the EtZn-mediated coupling reaction between dibromoketones and monobromo carbonyl compounds and the subsequent β-elimination with bromoacetyl bromide. Polysubstituted pyrroles were also prepared in one-pot by addition of primary amines after the coupling reaction.

Diethylzinc-Mediated Cross-Coupling Reactions between Dibromoketones and Monobromo Carbonyl Compounds.

A novel route to synthesize 1,4-dicarbonyl compounds is described. α,α-Dibromoketones generate zinc enolates through a diethylzinc-mediated halogen-metal exchange and react with α-bromocarbonyl compounds to furnish 1,4-dicarbonyl compounds via a second generation of zinc enolates. This cross-coupling reaction is enabled by the chemoselective formation of zinc enolates from α,α-dibromoketones in the presence of α-bromocarbonyl compounds.

Construction of chiral α--amine scaffolds amine-catalyzed asymmetric Mannich reactions of alkyl-substituted ketimines.

Stereoselective Mannich reactions of aldehydes with ketimines provide chiral β-amino aldehydes that bear an α--amine moiety. However, the structural variation of the ketimines is limited due to the formation of inseparable / isomers, low reactivity, and other synthetic difficulties. In this study, a highly diastereodivergent synthesis of hitherto difficult-to-access β-amino aldehydes that bear a chiral α--amine moiety was achieved using the amine-catalyzed Mannich reactions of aldehydes with less-activated -ketimines that bear both alkyl and alkynyl groups.

Synthesis of Phenylcyclopropane-Based Secondary Amine Catalysts and Their Applications in Enamine Catalysis.

A novel chiral motif based on a phenylcyclopropane scaffold has been designed, and a facile synthetic route to the key intermediate for the synthesis of phenylcyclopropane-based chiral secondary amines has been developed. Newly synthesized chiral amines function as effective catalysts for several asymmetric reactions through enamine intermediates.