A method has been developed for the synthesis of racemic α,α-disubstituted amino acids by a tandem alkylation process (''Tandem UPS'') on solid-support. Consecutive alkylations of Wang resin-bound benzophenone imines of glycine afforded unnatural, disubstituted amino acid derivatives. Automated chemical synthesis was used to efficiently optimize conditions for both formation and hydrolysis of resin-bound disubstituted benzophenone imines and to generate a matrix of disubstituted amino acid derivatives.