Asymmetric 1,4-michael addition reaction of azadienes with α-thiocyanoindanones catalyzed by bifunctional chiral squaramide

In this paper, the organocatalytic asymmetric 1,4-Michael addition reaction of azadienes and α-thiocyanoindanones was investigated. A series of chiral benzofuran compounds containing thiocyano group and quaternary carbon center were synthesized in moderate yields with good enantioselectivities (up to 90:10 er) and high diastereoselectivities (up to >95:5 dr). This is the first case of 1,4-Michael addition reaction using α-thiocyanoindanones to obtain a series of chiral thio-cyano compounds and further broaden the scope of application of azadiene substrates. In addition, a possible reaction mechanism is also described in the article.