Tin(II) chloride assisted synthesis of N-protected gamma-amino beta-keto esters through semipinacol rearrangement

A facile synthetic route for the preparation of N-protected gamma-amino beta-keto esters from amino aldehydes and ethyl diazoacetate is described. The two component coupling is facilitated by tin(II) chloride followed by semipinacol rearrangement leading to the product in quantitative yield. The reaction is mild, instantaneous and compatible with Boc-, Fmoc- and Cbz-amino protecting groups.