Abstract
Isobornyloxycarbonyl chloride (IBOC-Cl), which is a satisfactorily stable oil, was prepared from isoborneol and phosgene. The chloride, when allowed to react with amino acids, gave the corresponding isobornyloxycarbonyl (IBOC-)-amino acids. In most cases, the IBOC-amino acids could be obtained in crystalline form and in good yields. The IBOC-amino acids are smoothly cleaved by acid-catalyzed solvolysis with trifluoroacetic acid to yield the free amino acids. Since the IBOC-Cl is much easier to prepare than t-butyloxycarbonyl chloride, the new amino-masking method is considered to be of great use in the synthesis of complicated peptides.
