The first total synthesis of telephiose A

The first total synthesis of telephiose A (1), a novel trisaccharide ester having two acetyl groups and two benzoyl groups, was achieved by using glucosyl donor 6 and disaccharide acceptor 12. The crucial key step was the stereoselective construction of the β-d-glucosidic linkage featuring the neighboring group participation of the 2-O-N-phenylcarbamoyl group (of donor 6), which can be selectively deprotected in the presence of acetyl and benzoyl groups. Donor 6 was prepared from d-glucose in eight steps (33% yield), whereas acceptor 12 was prepared from sucrose in six steps (35% yield). Precursors 6 and 12 were reacted in subsequent reactions (five steps) to afford 1 in 22% yield.

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