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[摘要]：A sulfonamide-based protecting group (PG), (9H-fluoren-9-yl)methanesulfonyl (Fins), which can be used in a similar way to the well-established Fmoc PG, was developed. The advantages of this new PG were demonstrated in the successful formation of a phosphonamide between an N-Fms-protected alpha-phosphonoalanine monoester and secondary alkylamines, including (R)-2-phenylethylamine, (S)-phenylalanine tert-butyl ester (H-Phe-OtBu), H-Pro-Gly-OtBu, and H-Phe-Phe-OtBu, without formation of oxazaphospholine, which is a serious problem associated with the Fmoc PG The success should pave the way to the solid-phase synthesis of unnatural peptides substituted with c-amino phosphonic acid (AP) at essentially any arbitrary position without, significant modification of the Fmoc-based chemistry that has been accumulated since Carpino's report in 1970 The N-Fms-AP monomer would attract much attention in the field of peptide mimetics |
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