THE TETRAHYDROOXAZINONE WAY TO ENANTIOPURE ALPHA-AMINO-ACIDS - SYNTHESIS OF CIS AND TRANS 3-VINYL PIPECOLIC ACIDS VIA AN INTRAMOLECULAR REACTION BETWEEN AN IMINIUM ION AND AN ALLYLSILANE MOIETIES
C. Agami et al., THE TETRAHYDROOXAZINONE WAY TO ENANTIOPURE ALPHA-AMINO-ACIDS - SYNTHESIS OF CIS AND TRANS 3-VINYL PIPECOLIC ACIDS VIA AN INTRAMOLECULAR REACTION BETWEEN AN IMINIUM ION AND AN ALLYLSILANE MOIETIES, Tetrahedron, 54(35), 1998, pp. 10309-10316
Reaction of glyoxal with a derivative of (R)-phenylglycinol having an
allylsilane side-chain afforded a transient iminium ion. Intramolecula
r reaction of the iminium ion and the allylsilane moieties occurred in
a totally stereoselective way. Straightforward transformations ultima
tely led to enantiopure either cis or trans 3-vinyl pipecolic acid met
hyl ester. The stereochemical course of this reaction was rationalized
via AMI calculations. (C) 1998 Elsevier Science Ltd. All rights reser
ved.