N-Methoxycarbonyl-L-tert-leucine (abbreviated as MOC-L-tert-leucine) is an amino-protected amino acid derivative and a chiral pharmaceutical intermediate. In its molecular structure, the α-amino group of L-tert-leucine is protected by a methoxycarbonyl group (-COOCH₃), and it has a stable chiral configuration (S-configuration). It is widely used in the fields of peptide synthesis and asymmetric catalysis.

1. Peptide drug synthesis: As an N-terminal protected amino acid, it is used in solid-phase / liquid-phase peptide synthesis for the introduction of tert-leucine (Tle) units.

2. Pharmaceutical intermediate: A key building block for the synthesis of HIV protease inhibitors such as atazanavir.

3. Chiral ligand / catalyst: Used in asymmetric organic catalytic reactions.

4. Biochemical research: A tool molecule for protein / peptide modification and conformational studies.