Copper(i)-catalyzed asymmetric intramolecular C-arylation with ureas as the additives: highly enantioselective formation of spirooxindoles.

A cooperative catalytic strategy is developed for a copper-catalyzed asymmetric intramolecular C-arylation reaction with ureas as the co-catalysts. By forming hydrogen bonds with 1,3-dicarbonyl structures, ureas can activate the substrates, stabilize the carbanion intermediates and the products, and fix the syn-configurations of 1,3-dicarbonyl structures. They help enhance the reactivity, prevent side reactions and improve the enantioselectivities.

Stereospecific Synthesis of ( E)-5-Tetrasubstituted-ylidene-3,5-dihydro-4 H-imidazol-4-ones.

A stereospecific synthesis of ( E)-5-tetrasubstituted-ylidene-3,5-dihydro-4 H-imidazol-4-one derivatives is demonstrated through a cascade process by combination of a Michael addition and Boulton-Katritzky rearrangement. The method provides a simple and efficient approach for the synthesis of ( E)-5-tetrasubstituted-ylidene-3,5-dihydro-4 H-imidazol-4-ones from the reactions of N-(isoxazol-3-yl)-propiolamides or N-(1,2,4-oxadiazo-3-yl) propiolamides with N or C nucleophiles.

Copper(I)-Catalyzed Intramolecular Asymmetric Double C-Arylation for the Formation of Chiral Spirocyclic Bis-oxindoles.

A copper-catalyzed intramolecular asymmetric double C-arylation reaction was developed. The method provides a facile approach to chiral spiro bis-oxindoles in high yields and with good to excellent enantioselectivities. It also shows a broad substrate scope and good functional group tolerance. Density functional theory (DFT) calculations were conducted and revealed that the enantioselectivity is determined at the oxidative addition of Cu(I) into the second C-I bond.