ABSTRACT
A direct enantioselective vinylogous Mannich reaction of ketimines with γ-butenolide has been developed. Good yields and enantioselectivities were observed for the reaction of various ketimines by using a cinchona alkaloid amide/Zn(OTf)2 catalyst and Et3N. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts.
Subject(s)
4-Butyrolactone/analogs & derivatives , Cinchona Alkaloids/chemical synthesis , Imines/chemistry , Nitriles/chemistry , 4-Butyrolactone/chemical synthesis , 4-Butyrolactone/chemistry , Amides , Cinchona Alkaloids/chemistry , Mesylates/chemistry , Molecular Structure , StereoisomerismABSTRACT
Highly enantioselective desymmetrization of aziridines with TMSNCS has been developed. Good yield and enantioselectivity were observed by using novel chiral imidazoline-phosphoric acid catalysts. The obtained product can be converted to a chiral ß-aminothiol and a ß-aminosulfonic acid.
ABSTRACT
The enantioselective direct Mannich-type reaction of ketimines with α-isocyanoacetates has been developed. Excellent yields and enantioselectivity were observed for the reaction of various ketimines and α-isocyanoacetates using cinchona alkaloid/Cu(OTf)2 and a base. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α,ß-diamino acids.
Subject(s)
Acetates/chemistry , Cinchona Alkaloids/chemistry , Imines/chemistry , Nitriles/chemistry , Catalysis , Molecular Structure , StereoisomerismSubject(s)
Amides/chemistry , Cinchona Alkaloids/chemistry , Coordination Complexes/chemical synthesis , Furans/chemistry , Imines/chemistry , Nitriles/chemistry , Organometallic Compounds/chemistry , Catalysis , Coordination Complexes/chemistry , Ligands , Mannich Bases/chemistry , Models, Molecular , Molecular Structure , StereoisomerismABSTRACT
Small intestinal anisakiasis is a rare disease that is very difficult to diagnose, and its initial diagnosis is often surgical. However, it is typically a benign disease that resolves with conservative treatment, and unnecessary surgery can be avoided if it is appropriately diagnosed. This case report is an example of small intestinal obstruction caused by anisakiasis that resolved with conservative treatment. A 63-year-old man admitted to our department with acute abdominal pain. A history of raw fish (sushi) ingestion was recorded. Abdominal CT demonstrated small intestinal dilatation with wall thickening and contrast enhancement. Ascitic fluid was found on the liver surface and in the Douglas pouch. His IgE (RIST) was elevated, and he tested positive for the anti-Anisakis antibodies IgG and IgA. Small intestinal obstruction by anisakiasis was highly suspected and conservative treatment was performed, ileus tube, fasting, and fluid replacement. Symptoms quickly resolved, and he was discharged on the seventh day of admission. Small intestinal anisakiasis is a relatively uncommon disease, the diagnosis of which may be difficult. Because it is a self-limiting disease that usually resolves in 1-2 weeks, a conservative approach is advisable to avoid unnecessary surgery.
ABSTRACT
The first highly enantioselective desymmetrization of aziridines with phosphites has been developed. Excellent yields and enantioselectivities were observed for the reaction with various aziridines using a new class of readily accessible chiral catalysts derived from 9-amino-9-deoxy-epi-cinchona alkaloids. In studies probing the reaction mechanism, we observed some complexes for the cinchona alkaloid amide-Zn(II) by ESI-MS analysis.
Subject(s)
Amides/chemistry , Aziridines/chemistry , Cinchona Alkaloids/chemistry , Organometallic Compounds/chemistry , Organophosphonates/chemical synthesis , Phosphites/chemistry , Catalysis , Models, Molecular , Molecular Structure , Organophosphonates/chemistry , Stereoisomerism , Zinc/chemistryABSTRACT
Organocatalytic enantioselective hydrophosphonylation of ketimines using cinchona alkaloids and Na(2)CO(3) afforded products with high enantioselectivity. Both enantiomers of alpha-amino phosphonates can be prepared by using pseudoenantiomeric cinchona alkaloids. The catalyst loading of cinchona alkaloids can be reduced to 0.5 mol % without a significant loss of enantioselectivity.