Asymmetric Synthesis of cis-3,4-Dihydrocoumarins via [4 + 2] Cycloadditions Catalyzed by Amidine Derivatives.

A highly efficient chiral amidine derivative-catalyzed tandem Michael addition/lactonization of carboxylic acids and o-quinone methides (o-QMs) has been developed that enables the asymmetric synthesis of cis-3,4-dihydrocoumarins bearing contiguous tertiary stereogenic centers in high yields with excellent stereoselectivities.

Regioselective metal-free one-pot synthesis of functionalized 2-aminothiophene derivatives.

A facile metal-free synthesis of 2-aminothiophene derivatives by the reaction of 2-ynals with thioamides in alcohols has been developed. This transformation allows the assembly of 2-aminothienyl ether derivatives via a well-designed aldol condensation/regioselective intramolecular cyclization/conjugate addition cascade reaction and provides a straightforward synthetic protocol for constructing 2,3,5-trisubstituted 2-aminothiophenes.

Asymmetric Synthesis of 3,4-Dihydroquinolin-2-ones via a Stereoselective Palladium-Catalyzed Decarboxylative [4 + 2]- Cycloaddition.

An efficient, palladium-catalyzed, decarboxylative [4 + 2]-cycloaddition of 4-vinyl benzoxazinanones with carboxylic acids has been developed with the employment of P-chiral monophosphorus ligand BI-DIME, affording a series of structurally diverse 3,4-dihydroquinolin-2-ones bearing two contiguous stereogenic centers in moderate to good yields with good to excellent stereoselectivities.