Synthesis by conjugate radical addition of new heterocyclic amino acids with nucleobase side chains

N -(2-iodoethyl) and N -(3-iodopropyl)pyrimidines and purines undergo stereoselective conjugate radical addition with an optically active oxazolidinone acceptor to give syn -adducts that can be converted into amino acids carrying pyrimidine and purine (nucleobase) side chains.