Aminoacid precursors in protectedamino alcohol form are important synthons that can be used as building-blocks for the hemisynthesis of non-natural aminoacids. Serine can be used as a common starting material for the synthesis of such compounds differently protected. Particularly, protectedamino alcohols bearing an ethynyl and/or an iodoethynyl group can be used in cross-couplings, in 1,3-dipolar