Improved synthetic routes to the selenocysteine derivatives useful for Boc-based peptide synthesis with benzylic protection on the selenium atom

Selenocysteine (Sec) derivatives, i.e., Boc-Sec(MBn)-OH (1) and Boc-Sec(MPM)-OH (2), which are useful for chemical synthesis of selenopeptides, were obtained from L-serine in five steps with total yields of 73% and 74%, respectively.The enantiomeric excesses were confirmed to be >99% e.e. by optical resolution using a chiral column on HPLC.On the other hand, for the case of a Fmoc-protected Sec derivative, i.e., Fmoc-Sec(MPM)-OH, similar reactions resulted in low yields and partial racemization taking place.HO CO 2 H NH 2 L-serine 5 steps optimized conditions Se CO 2 H HN 1, R=Me (73%, >99% e.e.) 2, R=OMe (74%, >99% e.e.