The first total synthesis of the marine nucleoside Mycalisine B-a naturally occurring and structurally distinct 4,5-unsaturated 7-deazapurine nucleoside-has been accomplished in 10 linear steps with 27.5% overall yield from commercially available 1,2,3,5-tetra-O-acetyl-ribose and tetracyanoethylene. Key steps of the approach include: (1) I2 catalyzed acetonide formation from 1,2,3,5-tetra-O-acetylribose and acetone at large scale; (2) Vorbrüggen glycosylation using N4-benzoyl-5-cyano-6-bromo-7H-pyrrolo[2,3-d]pyrimidine as a nucleobase to avoid formation of N-3 isomer; (3) mild and scalable reaction conditions.

中文翻译：

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Mycalisine B 的全合成。

海洋核苷 Mycalisine Ba 天然存在且结构独特的 4,5-不饱和 7-脱氮嘌呤核苷的首次全合成已通过 10 个线性步骤完成，市售 1,2,3,5-四-的总产率为 27.5% O-乙酰基核糖和四氰乙烯。该方法的关键步骤包括：（1）I2催化1,2,3,5-四-O-乙酰核糖和丙酮大规模形成丙酮化物；(2)使用N4-苯甲酰基-5-氰基-6-溴-7H-吡咯并[2,3-d]嘧啶作为核碱基进行Vorbrüggen糖基化以避免N-3异构体的形成；(3)反应条件温和且可规模化。