Stereocontrolled Transformation of Nitrohexofuranoses into Cyclopentylamines via 2-Oxabicyclo[2.2.1]heptanes. Part 6. Synthesis and Incorporation into Peptides of the First Reported 2,3-Dihydroxycyclopentanecarboxylic Acid.

Abstract Herein we report the intramolecular alkylation of nitronates of methyl-5- O -benzyl-3,6-deoxy-6-nitro-β- d -glucofuranoside and methyl-5- O -benzyl-3,6-deoxy-6-nitro-α- d -glucofuranoside into the corresponding 2-oxabicyclo[2.2.1]heptane derivatives. Similarly, methyl-3- O -benzyl-5-deoxy-5-nitromethyl-β- d -xylofuranoside and methyl-3- O -benzyl-5-deoxy-5-nitromethyl-α- d -xylofuranoside were cyclized to (1 R ,3 R ,4 S ,5 R ,7 R )-7-benzyloxy-3-methoxy-5-nitro-2-oxabicyclo[2.2.1]heptane and (1 R ,3 S ,4 S ,5 R ,7 R )-7-benzyloxy-3-methoxy-5-nitro-2-oxabicyclo[2.2.1]heptane, respectively. These 2-oxabicyclo[2.2.1]heptane derivatives were eventually transformed into enantiopure methyl (1 S ,2 S ,3 R ,4 S ,5 R )-2-amino-2,3-dihydroxycyclopentanecarboxylate and this novel β-amino acid was incorporated into peptides.