The tetrahydrooxazinone way to enantiopure α-amino acids: Synthesis of cis and trans 3-vinyl pipecolic acids via an intramolecular reaction between an iminium ion and an allylsilane moieties

Article abstract of DOI:10.1016/S0040-4020(98)00486-4

Reaction of glyoxal with a derivative of (R)-phenylglycinol having an allylsilane side-chain afforded a transient iminium ion. Intramolecular reaction of the iminium ion and the allylsilane moieties occurred in a totally stereoselective way. Straightforward transformations ultimately led to enantiopure either cis or trans 3-vinyl pipecolic acid methyl ester. The stereochemical course of this reaction was rationalized via AMI calculations.