Mari Kikuchi, H. Konno
Aug 26, 2013
Citations
0
Influential Citations
9
Citations
Journal
Tetrahedron
Abstract
Abstract The improved synthesis of protected d -allothreonine derivatives [Fmoc- d -alloThr(tBu)-OH (1) and Fmoc- d -alloThr-OtBu (2)] is described. The epimerization of cheap l -threonine ( l -Thr) (3) with catalytic salicylaldehyde afforded a mixture of l -Thr (3) and d -alloThr (4) and separation of ammonium salt gave d -alloThr (4) in 96% de. The chemoselective deprotection of tert-butyl ether or tert-butyl ester of Fmoc- d -alloThr(tBu)-OtBu (5) easily succeeded in converting Fmoc- d -alloThr(tBu)-OH (1) or Fmoc- d -alloThr-OtBu (2), respectively.