Synthesis of Functionalized L-Cysteine and L-Methionine by Reaction with Electron-Deficient Acetylenes

A novel families of nonconventionally functionalized amino acids have been synthesized in almost quantitative yields by chemo-, regio- and stereospecific addition of L-cysteine and L-methionine to electron-deficient functionalized acetylenes (cyanoacetylenes and methyl 4-hydroxy-4-methylpent-2-ynoate) under mild conditions (water, r.t., 2-5 h). Thus, for the first time, the uncommonly functionalized optically active amino acids composing Of L-cysteine and L-methionine structural units along with cinnamic acid, dihydrofuranone, iminodihydrofuran, and other biologically important functionalities are readily available.