Rhodium(I)-Catalyzed Diastereoselective Cycloisomerization of Enynes with Tethered (S)-2-Methyl-2-propanesulfinyl Imine

Palladium-Catalyzed Aminoalkylative Cyclization Enables Modular Synthesis of Exocyclic 1,3-Dienes

A novel and efficient palladium-catalyzed regioselective and stereodivergent ring-closing reaction of aminoenynes with aldehydes and boronic acids or hydrosilane is developed. This three-component reaction allows for the modular synthesis of a series of exocyclic 1,3-dienes bearing 5- to 8-membered saturated N-heterocycles. The reactions utilize a simple Pd-catalyst and work with broad range of aminoenynes, aldehydes and organometallic reagents under mild reaction conditions. The products represent useful intermediates for chemical synthesis due to the versatility of the conjugated diene. Preliminary mechanistic details of the method are also revealed.

Cobalt(I)-Catalyzed Reductive Cyclization of Enynes and Diynes Using Hydrogen Gas as a Reductant

Reductive cyclization of enynes and diynes by using H₂ gas as a reductant was realized, and the corresponding cyclized products were obtained in good yields without olefin isomerization and over-reduction of the products. By an experiment using D₂ instead of H₂, it was confirmed that H₂ unambiguously operates as a reductant in this reaction. The protocol of the reaction is very economical and user-friendly, using air- and moisture-stable CoBr₂·6H₂O and 1 atm of pressure of H₂.

Recent advances in rhodium-catalyzed asymmetric synthesis of heterocycles

Heterocycles are crucial structural motifs that are ubiquitously present in biologically active natural products and pharmaceutically important compounds. Over the past few decades, great attention has been paid to develop efficient methodologies for the construction of diverse enantioenriched heterocyclic frameworks. This review focuses on the recent impressive progress and advances in the asymmetric synthesis of heterocycles under rhodium catalysis.