First asymmetric synthesis of a 6-alkoxy-5,6-dihydro-1,3-oxazine: a promising enantioselective route to beta-amido aldehydes
[reaction: see text] The 1,3-oxazine route to enantiopure beta-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.
Gizecki
P
Laboratoire de Synthese Organique, Associe au CNRS, Universite du Maine, Le Mans, France.
Dhal
R
Toupet
L
Dujardin
G