Organocatalytic asymmetric synthesis of propargylamines with two adjacent stereocenters: Mannich-type reactions of in situ generated C-alkynyl imines with β-keto esters
Side by side: The title reaction is catalyzed by the chiral Bronsted acid (S)-1, and affords hitherto less accessible chiral propargylamines, having two adjacent stereocenters, in good to excellent diastereo- and enantioselectivities. Boc=tert-butoxycarbonyl. Copyright
Kano, Taichi,Yurino, Taiga,Maruoka, Keiji
supporting information
p. 11509 - 11512
(2013/11/06)
RETRACTED ARTICLE: Enantioselective organocatalytic hantzsch synthesis of polyhydroquinolines
The four-component Hantzsch reaction provides access to pharmaceutically important dihydropyridines. To expand the utility of this method, we have developed a route under organocatalytic conditions with good yields and excellent ee's. Through catalyst scr
Evans, Christopher G.,Gestwicki, Jason E.
supporting information; experimental part
p. 2957 - 2959
(2009/12/05)
Chiral lithium salts of phosphoric acids as Lewis acid-base conjugate catalysts for the enantioselective cyanosilylation of ketones
The catalytic enantioselective cyanosilylation of aromatic ketones was developed by using chiral lithium salts of (R)-BINOL- or (S)-BINAM-derived phosphoric acid compounds. In the presence of 10 mol% of chiral conjugate lithium salts, the corresponding tertiary cyanohydrins were obtained in high yields with moderate to high enantio-selectivities. This is the first efficient example of asymmetric catalysis using lithium salts of synthetically useful chiral phosphoric acid compounds. A possible catalytic mechanism and transition states are also discussed as a preliminary working hypothesis.