Diels guanidine catalyzed

In 2006, Tan and co-workers reported the first asymmetric guanidine catalyzed Diels-Alder addition of anthrone to maleimides (Scheme 75) [130], The authors observed very high yields and enantioselectivities using a derivative of Corey s C2-symmetric bicyclic gnanidine catalyst. The addition of anthrones to maleimide also worked well for snbstitnted anthrones. Interestingly, the anthors observed the oxidized prodnct when the anthrone was substituted at the meto-positions (Scheme 76). 

Scheme 38.29 Chiral guanidine catalyzed hetero-Diels-Alder reactions.

---