Squaramide-Catalyzed Asymmetric Michael Addition Reaction of α-Azidoindanones with Azadienes

An organocatalytic asymmetric Michael addition reaction of α-azidoindanones with azadienes was developed. A series of optically active benzofuran derivatives containing an azido group was obtained in 32–82% yields with 66:34–>95:5 dr and 53:47–90:10 er. These products demonstrate excellent stability. Furthermore, when the template reaction was scaled up, the reaction efficiency remained consistent. To further assess the practicality of this catalytic asymmetric reaction, two derivative reactions were successfully conducted, affording the corresponding derivative products in good yields and with high stereoselectivities. In addition, a plausible reaction mechanism was also proposed.