N-Boc-D-3-Benzothienylalanine is a non-natural, protected amino acid derivative. Its structure features a D-configuration alanine backbone where the side chain is substituted with a benzothiophene ring, and the amino group is protected by a tert-butoxycarbonyl (Boc) group. This combination of a heterocyclic aromatic system and a chiral, protected amino acid scaffold makes it a specialized building block. This compound is primarily used in peptide chemistry and medicinal chemistry research as a key intermediate. The benzothiophene moiety can impart specific conformational, electronic, or hydrophobic properties to peptides, potentially enhancing their binding affinity, metabolic stability, or membrane permeability. It is particularly valuable for the synthesis of novel peptide-based drug candidates, enzyme inhibitors, or probes where the introduction of a constrained, aromatic heterocycle is desired to modulate biological activity. The Boc protecting group allows for selective deprotection under mild acidic conditions, facilitating its incorporation into solid-phase or solution-phase peptide synthesis protocols. As a derivative of D-phenylalanine, it is also used to study the effects of chirality and side-chain modification on peptide structure and function.