An asymmetric synthesis ofl-[2-13C]aspartic acid from sodium [2-13C]acetate

A Stereoselective aza-Prins Reaction: Rapid Access to Enantiopure Piperidines and Pipecolic Acids

“…Therefore, we prepared mono ( 8 ) and diphenyl ( 7 ) , allylmorpholin-2-ones in both enantiomeric forms in just 4 steps, as two new chiral platforms containing a homoallylic amine. Following the rationale presented in Scheme (2), the phenyl substituents were chosen, as these would both facilitate rapid removal of part of the chiral platform post Prins cyclization and crucially block one face from anion trapping.…”

A simple convenient synthesis of l‐[4‐13C]glutamine

“…We have already reported asymmetric syntheses of various specific 13 C-labeled amino acids from Dellaria's oxazinone 12 or its 13 C-labeled form as the chiral optically active glycine equivalent. [13][14][15][16] For example, asymmetric syntheses of L-[4-13 C] glutamic acid and L-[4-13 C]glutamine (1) were achieved by using diastereoselective Michael addition of the oxazinone to a 13 Clabeled acrylate, which was prepared from sodium [2-13 C]acetate in a 16 total steps and 2% overall yield. 17 In this method, it is possible to label L-glutamine with 13 C at specific positions-C1, C2, C4, and/or C5-but many steps are required, including the laborious preparation of labeled acrylate for 13 C labeling at just the 4-position.…”