Ready access to constrained, multifunctionalized, hydrolytically stable amino acids has been established by the synthesis of their direct precursors using 2,5-anhydro-3-azido-3-deoxy-D-altrose (a 'formyl azido-C-glycofuranoside'), or its readily available, stable synthetic equivalent [(1R) and (1S)-2,5-anhydro-3-azido-4,6-O-benzylidene-3-deoxy-1-fluoro-1-O-methyl-D-altritol], as novel molecular scaffolds. (C) 2005 Elsevier Ltd. All rights reserved.
Synthesis of cyclically constrained sugar derived α/β- and α/γ-peptides
A general approach to enantiopure conformationally constrained sugar derived α/β- and α/γ-peptides has been established. Five-membered ring α/β-peptides were synthesized via formyl C-glycofuranosides, easy available from hexose-derived azido-2-equatorial-OH-glycopyranosides by DAST-promoted ring contraction. By means of a regioselective oxidation with TEMPO at C-6 of hexose-derived 3-azido glycopyranosides as the key step, two- and three-residue α/γ-peptides having a six-membered ring were obtained in good yields and under very simple experimental conditions.
目前已经建立了一种通用方法,可以对映纯构象约束糖衍生的δ/δ²-和δ/δ³-肽进行合成。五元环δ±/δ²-肽是通过甲酰基 C-甘呋喃糖苷合成的,而甲酰基 C-甘呋喃糖苷是通过 DAST 促进的缩环作用从源自己糖的叠氮-2-赤道-OH-甘吡喃糖苷中容易获得的。作为关键步骤,通过在源自己糖的 3-叠氮吡喃糖苷的 C-6 位使用 TEMPO 进行区域选择性氧化,在非常简单的实验条件下,获得了具有六元环的双残基和三残基δ/δ³-肽,产量很高。