Chiral Brønsted Base Catalyzed Enantioselective Reactions
Date : October 25, 2012 17:30 ~
Speaker : Tan Choon Hong(Nanyang Technological University)
Location : SangSan Math Science Bldg.
Date : 2012. 10. 25, 5:30 PM
Place : SangSan Math Science Bldg.
-Abstract-
We are keen to develop chiral guanidine as general brønsted base catalyst. We found them to be excellent enantioselective catalysts for Michael, Phospha-Michael and Diels-Alder reactions. In this seminar, we would like to present these reaction and two other reactions relating to the enantioselective transfer of protons. In the first reaction, the conjugate addition of arylthiol to 2-phthalimidoacrylate generates a pro-chiral transient enolate which upon protonation gave cysteine analogues with high enantioselectivities. In the second reaction, we showed that guanidine catalyze the 1,3-proton shift reaction, allowing chiral allenes to be prepared directly from alkynes.