One-Pot Synthesis of Enantioenriched β-Amino Secondary Amides via an Enantioselective [4+2] Cycloaddition Reaction of Vinyl Azides with N-Acyl Imines Catalyzed by a Chiral Br?nsted Acid
A catalytic enantioselective synthesis of β-amino secondary amides was achieved using vinyl azides as the enamine-type nucleophile and chiral N-Tf phosphoramide as the chiral Br?nsted acid catalyst through a five-step sequential transformation in one pot.
Kinetic resolution of oxazinones: An organocatalytic approach to enantiomerically pure β-amino acids
(Chemical Equation Presented) A profitable split: An organocatalytic resolution converts readily available racemic oxazinones 1 into valuable enantiomerically pure β-amino acid derivatives 2 (> 99% ee of the remaining 1 at 53% conversion; 88% ee of the ester 2). This catalytic ring-opening reaction requires as little as 1 mol% of the modular and readily accessible thiourea organocatalyst 3.
First asymmetric synthesis of a 6-alkoxy-5,6-dihydro-1,3-oxazine: A promising enantioselective route to β-amido aldehydes
equation presented The 1,3-oxazine route to enantiopure β-amido aldehydes was investigated. Heterocycloaddition of the N-acyl imine 1 with (R)-O-vinylpantolactone provided the stable dihydroxazine 4c. High diastereocontrols were observed when using Yb(fod)3-catalyzed or SnCl4-mediated conditions, thus leading after quantitative hydrolysis to (R)-N-benzoyl-3-phenylpropanal with >98% ee.