How is N-[(9H-Fluoren-9-ylmethoxy)carbonyl]-L-isovaline (CAS: 857478-30-9) typically synthesized?

N-[(9H-Fluoren-9-ylmethoxy)carbonyl]-L-isovaline is synthesized through a multi-step process involving the coupling of fluorene-9-methanol with isovaline. The synthesis commonly uses a protected amino acid approach with a carbodiimide coupling reagent. The final product is obtained with good yield and selectivity under mild conditions, often performed under anhydrous conditions to prevent side reactions.