Two novel 5.4-spirolactam systems have been developed as@-turn mimics. The (R)-5.4- spirolactam system of 4 was designed to mimic the type-I1 &turn, and the (S)-5.4-spirolactam system of 5 was designed to mimic the type-11'@-turn. The 5.4-spirolactam dipeptide mimic 11 was synthesized in racemic form from pipecolic acid. This intermediate was then converted to the diastereoisomeric mixture of peptidomimetics 4 and 5, which were ...