182316-01-4Relevant academic research and scientific papers
Design, synthesis, and 1,3-dipolar cycloaddition of (5R)- [and (5S)]-5,6-dihydro-5-phenyl-2H-1,4-oxazin-2-one N-oxides as chiral (E)-geometry-fixed α-alkoxycarbonylnitrones
Tamura,Gotanda,Yoshino,Morita,Terashima,Kikuchi,Miyawaki,Mita,Yamashita,Ishibashi,Sakamoto
, p. 8544 - 8551 (2007/10/03)
Optically pure (5R)- [and (5S)]-5,6-dihydro-5-phenyl-2H-1,4-oxazin-2-one N-oxides [(5R)- and (5S)-2] were designed as chiral (E)-geometry-fixed α-alkoxycarbonylnitrones 1. The nitrones (5R)- and (5S)-2 were synthesized by three-step oxidation of (R)- and (S)-phenylglycinols [(R)- and (S)-3], condensation of the resulting (R)- and (S)-2-hydroxylamino-2-phenylethanols [(R)- and (S)-5] with glyoxylic acid, and cyclization of the intermediary nitrones (R)- and (S)-6b. The nitrone (5R)-2 reacted with olefins 7-14 under mild conditions to afford the corresponding cycloadducts 15-22 as the main products via the least sterically demanding exo modes. Cycloadduct 30 obtained from (5S)-2 and cyclopentadiene was effectively elaborated to (1S,4S,5R)-4-benzyloxycarbonylamino-2-oxabicyclo[3.3.0]oct-7-en-3-one (28), the key synthetic intermediate of carbocyclic polyoxin C.
Preparation and evaluation of a cyclic acyl nitrone as a synthon for stereospecific α-amino acid synthesis
Baldwin, Steven W.,Young, Bruce G.,McPhail, Andrew T.
, p. 6819 - 6822 (2007/10/03)
The preparation and characterization of cyclic optically active (5R)- 3,4,5,6-tetrahydro-5-phenyl-2H-1,4-oxazin-2-one-N-oxide (2) is described. This nitrone, which is viewed as a template for the synthesis of γ- oxygenated α-amino acids, reacts with alkenes efficiently and with high stereospecificity.
