a method of solid phase peptide synthesis and a reusable insoluble polymer resin having functional groups of the formula resin -- nhrnhco . sub . n oh wherein r is an branched or straight chain alkyl or cycloalkyl group having 2 to 20 carbon atoms , an aromatic group , substituted aromatic group , heterocyclic group or substituted heterocyclic group preferably 1 , 4 - dimethylcyclohexane , and n is an integer , preferably 3 . phosphorylation followed by reaction with a diol , preferably 1 , 4 - bisbenzene , affords a substrate upon which peptides may be synthesized by repeated deprotection and coupling with protected amino acids .