β-Substituted β-amino acids, β-substituted β-amino acid derivatives, and β-substituted β-amino acid analogs and (bio)isosteres and their use as chemotherapeutic agents are disclosed. The β-substituted β-amino acid derivatives and β-substituted β-amino acid analogs and (bio)isosteres are selective LAT1/4F2hc substrates and exhibit rapid uptake and retention in tumors expressing the LAT1/4F2hc transporter. Methods of synthesizing the β-substituted β-amino acid derivatives and β-substituted β-amino acid analogs and methods of using the compounds for treating cancer are also disclosed. The β-substituted β-amino acid derivatives and β-substituted β-amino acid analogs exhibit selective uptake in tumor cells expressing the LAT1/4F2hc transporter and accumulate in cancerous cells when administered to a subject in vivo. The β-substituted β-amino acid derivatives and β-substituted β-amino acid analogs and (bio)isosteres exhibit cytotoxicity toward several tumor types.