Derivatisation of 1,3,4,6-Tetra-O-Benzoyl-α-D-Fructofuranose at the Anomeric Site :O-Alkylation,O-Acylation,O-Arylation, Amination and Selenation Reactions

Abstract

Treatment of D-fructose with benzoyl chloride gave either 1,2,3,4,6-penta-O-benzoyl-α-D-fructofuranose or 1,3,4,6-tetra-O-benzoyl-α-D-fructofuranose (lα) which with methanol, 2-nitrophenol, or 4-nitrophenol in the presence of the Mitsunobu reagents, diisopropyl azodicarboxylate and triphenylphosphine, gave the corresponding fructofuranosides in good yield; an analogous reaction with 4-methoxybenzylamine gave the corresponding D-fructo-furanosylamine. Alkylation with isopropyl alcohol or t-butyl alcohol was complicated by competition from transesterification and fructose disaccharide formation. There was little or no inversion in these reactions. The 2-O-acetyl derivative of 1 reacted with selenophenol and diethyl ether-boron trifluoride to give phenyl l-deoxy-3,4,6-tri-O-benzoyl-2-seleno-α,β-D-fructofuranose as a minor product and phenyl l,3,4,6-tetra-O-benzoyl-2-seleno-α,β-D-fructo-furanose which with tris(trimethylsilyl)silane and AIBN gave l,3,4,6-tetra-O-benzoyl-2,5-anhydro-D-mannitol and l,3,4,6-tetra-O-benzoyl-2,5-anhydro-D-glucitol. Treatment of the acetyl derivative of 1 with Me₃SiN₃ gave l,3,4,6-tetra-O-benzoyl-α,β-D-fructofuranosyl azide which was hydrogenated to afford the corresponding fructofuranosylamine. This compound rearranged to give N-benzoyl-1,4,6,-tri-O-benzoyl-β-D-fructofuranosylarnine