Serine as chiral educt for the practical synthesis of enantiopure N-protected beta-hydroxyvaline.
N-tert-Butyloxycarbonyl- and N-benzenesulfonyl-beta-hydroxyvalines 1a and 1b were, respectively, synthesized in enantiomerically pure form by a two-step protocol from their enantiomeric N-protected serine methyl esters 2a and 2b. The addition of CH(3)MgBr to 2a and 2b provided diols 3a and 3b, respectively as major products in 83% and 81% yields. Selective oxidation of diols 3a and 3b was performed using a TEMPO, NaClO(2), NaOCl cocktail in 96% and 93% respective yields. This two-step process effectively furnished multigram amounts of enantiopure N-Boc-beta-hydroxyvaline 1a.
Dettwiler
James E
JE
Département de Chimie, Université de Montréal, C.P. 6128, Succursale Centre Ville, Montréal, Québec, Canada H3C 3J7.
Lubell
William D
WD
D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D015394:Molecular Structure; D012694:Serine / Q000737:chemistry*; D013237:Stereoisomerism; D014633:Valine / Q000031:analogs & derivatives* / Q000138:chemical synthesis*
C474458:N-benzenesulfonyl-beta-hydroxyvaline; C474457:N-tert-butyloxycarbonyl-beta-hydroxyvaline; D012694:Serine; D014633:Valine