Carbene-Catalyzed Enantioselective Aromatic N-Nucleophilic Addition of Heteroarenes to Ketones
The aromatic nitrogen atoms of heteroarylaldehydes are activated by carbene catalysts to react with ketone electrophiles. Multi-functionalized cyclic N,O-acetal products are afforded in good to excellent yields and optical purities. Our reaction involves the formation of an unprecedented aza-fulvene-type acylazolium intermediate. A broad range of N-heteroaromatic aldehydes and electron-deficient ketone substrates works effectively in this transformation. Several of the chiral N,O-acetal products afforded through this protocol exhibit excellent antibacterial activities against Ralstonia solanacearum (Rs) and are valuable in the development of novel agrichemicals for plant protection.
Scaffold-inspired enantioselective synthesis of biologically important spiro[pyrrolidin-3,2'-oxindoles] with structural diversity through catalytic isatin-derived 1,3-dipolar cycloadditions
Catalytic asymmetric construction of the biologically important spiro[pyrrolidin-3,2'-oxindole] scaffold with contiguous quaternary stereogenic centers in excellent stereoselectivities (up to >99:1 d.r., 98 % ee) has been established by using an organocat