- An improved synthesis of optically pure 4-Boc-5,6-diphenylmorpholin-2-one and 4-Cbz-5,6-diphenylmorpholin-2-one
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A convenient synthesis of optically pure 4-Boc-5,6-diphenylmorpholin-2-one and 4-Cbz-5,6-diphenylmorpholin-2-one by reaction of (+)- or (-)-2-amino-1,2-diphenylethanol with ethyl bromoacetate, followed by N-protection, and p-TsOH-mediated ring-closure is
- Dastlik, Kim A.,Sundermeier, Uta,Johns, Deidre M.,Chen, Yuyin,Williams, Robert M.
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p. 693 - 696
(2007/10/03)
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- Optically active carboalkylated amino alcohols and their utilization in optical resolution
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A carboalkylated amino alcohol having each of the below shown formulae is novel and optically active. A separating agent comprising the alcohol and a support is effectively useful to separate a variety of racemates for example with chromatography. The alc
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- Practical Asymmetric Syntheses of α-Amino Acids through Carbon-Carbon Bond Constructions on Electrophilic Glycine Templates
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The optically active D- and L-erythro-4-(benzyloxycarbonyl)-5,6-diphenyl-2,3,5,6-tetrahydro-4H-1,4-oxazin-2-ones (3) and D- and L-erythro-4-(tert-butoxycarbonyl)-5,6-diphenyl-2,3,5,6-tetrahydro-4H-1,4-oxazin-2-ones (3) can be efficiently brominated to serve as electrophilic glycine templates for the asymmetric synthesis of amino acids.It was found that coupling to these templates can proceed with either net retention or net inversion of stereochemistry.The final deblocking to the amino acids is accomplished with either dissolving-metal reduction or catalytic hydrogenolysis.The syntheses of β-ethyl aspartic acid, norvaline, allylglycine, alanine, norleucine, homophenylalanine, p-methoxyhomophenylalanine, cyclopentylglycine, and cyclopentenylglycine and a formal synthesis of clavalanine are described.In addition, the direct asymmetric syntheses of N-t-BOC-allylglycine and N-t-BOC-cyclopentenylglycine are described.
- Williams, Robert M.,Sinclair, Peter J.,Zhai, Dongguan,Chen, Daimo
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p. 1547 - 1557
(2007/10/02)
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- Novel Chiral Stationary Phases for the Resolution of the Enantiomers of Amino Acids by Ligand Exchange Chromatography
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Novel chemically bonded chiral stationary phases (CSP's) derived from (1R,2S)-2-carboxymethylamino-1,2-diphenylethanol and from (1S,2S)-2-carboxymethylamino-1,2-diphenylethanol were prepared.The ligand exchange chromatography on these CSP's was found to b
- Yuki, Yoichi,Saigo, Kazuhiko,Tachibana, Kouzou,Hasegawa, Masaki
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p. 1347 - 1350
(2007/10/02)
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