Six achiral N-phthaloyl protected α,α-disubstituted β-amino acids were synthesized, and used to construct a 96 compound library of 1,2,3,4-tetrahydroisoquinoline conjugates of β-peptides on a solid support. The library synthesis consisted of attachment of an appropriately 5-O-tethered 1,2,3,4-tetrahydroisoquinoline via the N-2 atom to a vinyl sulfonyl support, elongation of the deprotected 5-O-tether by repeated peptide coupling, quaternarization of N-2 with alkylamines and release of the β-peptide conjugate into solution with triethylamine.