Methyl N-unprotected R-amino esters are important intermediates in organic synthesis. 1 They can be conveniently prepared by a Fisher-type esterification of the corresponding free R-amino acids in methanol using gaseous HCl, 1a SOCl2, 1b or TMSCl. 1c In addition, an increasing number of methods have been developed for the preparation of R-amino acids with the R-nitrogen atom already protected by a Boc group. 2-7 For example, oxidations of ...