Direct Enantioselective Brønsted Acid Catalyzed N-Acyliminium Cyclization Cascades of Tryptamines and Ketoacids
摘要:
A direct enantio- and diastereoselective N-acyliminium cyclization cascade through chiral phosphoric acid catalyzed condensation of tryptamines with gamma- and delta-ketoacid derivatives to provide architecturally complex heterocycles has been developed. The reaction is technically simple to perform, atom-efficient, and broad in scope. Employing 10 mol % of (R)-BINOL derived chiral phosphoric acids in refluxing toluene allowed the polycyclic product materials to be generated in good yields (53-99%) and moderate to high enantioselectivities (68-98% ee).
Efficient Organocatalytic Michael Addition Reaction of β−Ketoesters under High Pressure
作者:Hiyoshizo Kotsuki、Maya Moritaka、Keiji Nakano
DOI:10.3987/com-13-12818
日期:——
The Michael addition reaction of beta-ketoesters was efficiently promoted by a cooperative dual catalyst system composed by DMAP and thiourea A under high-pressure conditions (0.8 GPa) in toluene. The expected relatively congested adducts of 1,5-dicarbonyl compounds were prepared in high to excellent yield.