New Reagents and Methods for the Synthesis of Peptides, β-Lactams and Oligonucleotides

Several schemes of peptide and β-lactam synthesis by 4 CC are discussed, and the chemistry of some associated reagents is described: The resolution of racemic α- ferrocenyl isobutylamine by (-)-diacetone -2-keto-gulonic acid yields either enantiomer, depending on the solvent used. 1-cyclohexenyl isocyanide is obtained from 2-cyclohexenyl isocyanide by base catalyzed-isome-rization. Some isocyanides are presented whose 4 CC products contain carbonamide groups that can be converted into activated carboxyl groups. The preparation of L-N -phthaloyl α, β-diaminoproprionic acid, a precursor of nocardicine and analogs, from L-asparagine is presented.