Used in the synthesis of paclitaxel (Taxol), a potent anticancer drug, Boc-3-Phenylisoserine serves as a key chiral building block. Its protected functional groups allow selective coupling to the taxane core, enabling efficient construction of the C-13 side chain essential for biological activity. Widely employed in pharmaceutical research, it supports the development of taxane analogs with improved solubility, efficacy, or reduced resistance. Also utilized in solid-phase peptide synthesis and as an intermediate in preparing other bioactive molecules where stereochemistry and side-chain functionality are critical.