N-(tert-Butoxycarbonyl)-L-alanine N′-methoxy-N′-methylamide is a Boc-protected derivative of L-alanine featuring a Weinreb amide (N-methoxy-N-methylamide) at the carboxyl terminus. It is widely used in organic and peptide synthesis for the controlled generation of aldehydes or ketones from amino acids via selective nucleophilic addition to the Weinreb functionality, avoiding over-addition common with other amides. The Boc group ensures amino group protection and stability under standard synthesis conditions, including compatibility with solid-phase peptide synthesis protocols. This reagent is essential for constructing complex peptides, peptidomimetics, and natural products where precise C-terminal modification and functional group compatibility are required.