N-bis-silylation of α-amino acids: "benzostabases" as amino protecting group

Article abstract of DOI:10.1016/S0040-4020(01)80720-1

N-Bis-trimethylsilylation of α-amino acids using the powerful trimethylsilyl triflate reagent is difficult, and is rendered impossible in the case of bulky side-chains (valine). However, favorable entropy changes resulting from a cyclization reaction allow the formation of "benzostabase" N-diprotections regardless of the side-chain bulk.