Boc chemistry was first described in the 1950s and requires acidic conditions for deprotection, while Fmoc, which was not reported for another twenty years, is cleaved under mild, basic conditions (3,4,5,6). Because of the mild deprotection conditions, Fmoc chemistry is more commonly used in commercial settings because of the higher quality and greater yield, while Boc is preferred for complex peptide synthesis or when non-natural peptides or analogs that are base-sensitive are required.