Highly enantioselective synthesis of both enantiomers of tetrahydroquinoxaline derivatives Ir-catalyzed asymmetric hydrogenation.

A novel Ir-catalyzed asymmetric hydrogenation protocol for the synthesis of chiral tetrahydroquinoxaline (THQ) derivatives has been developed. By simply adjusting the reaction solvent, both enantiomers of mono-substituted chiral THQs could be selectively obtained in high yields with excellent enantioselectivities (toluene/dioxane: up to 93% yield and 98% ee (); EtOH: up to 83% yield and 93% ee ()). For 2,3-disubstituted chiral THQs, the -hydrogenation products were obtained with up to 95% yield, 20 : 1 dr, and 94% ee.

Copper-catalyzed asymmetric allylic substitution of racemic/ substrates.

The synthesis of enantiomerically pure compounds is a pivotal subject in the field of chemistry, with enantioselective catalysis currently standing as the primary approach for delivering specific enantiomers. Among these strategies, Cu-catalyzed asymmetric allylic substitution (AAS) is significant and irreplaceable, especially when it comes to the use of non-stabilized nucleophiles (p > 25). Although Cu-catalyzed AAS of prochiral substrates has also been widely developed, methodologies involving racemic/ substrates are highly desirable, as the substrates undergo dynamic processes to give single enantiomer products.

Highly enantioselective synthesis of both tetrahydroquinoxalines and dihydroquinoxalinones Rh-thiourea catalyzed asymmetric hydrogenation.

Chiral tetrahydroquinoxalines and dihydroquinoxalinones represent the core structure of many bioactive molecules. Herein, a simple and efficient Rh-thiourea-catalyzed asymmetric hydrogenation for enantiopure tetrahydroquinoxalines and dihydroquinoxalinones was developed under 1 MPa H pressure at room temperature. The reaction was magnified to the gram scale furnishing the desired products with undamaged yield and enantioselectivity.

Copper-catalyzed asymmetric allylic alkylation of racemic inert cyclic allylic ethers under batch and flow conditions.

Highly enantioselective Cu-catalyzed asymmetric allylic alkylation of racemic inert cyclic allylic ethers is accomplished in this work. The use of Grignard reagents in combination with BF·OEt and CuBr·SMe/L2 is the key to enable employment of long-challenging low reactive allylic substrates in this AAA reaction. In addition, the approach exhibited a remarkable superiority in the construction of a stereogenic center involving challenging sterically hindered nucleophiles for both primary and secondary alkyl groups.