Preparation and properties of nα‐9‐fluorenylmethyloxycarbonylamino acids bearing tert.‐butyl side chain protection

The preparation is described by several Nalpha-9-fluorenylmethyloxycarbonylamino acids and derivatives bearing tert.-butyl type side-chain protection of amine, carboxyl, guanido, hydroxyl, imidazol, and sulfhydryl functionalities. Physicochemical properties of these compounds have been determined. Cleavage of the Fmoc group by various amines appears to depend on the base strength and steric hindrance. Premature deblocking of Fmoc group by amine on solid support is very slow and may be negligible under the conditions of solid-phase synthesis.