is challenging. The de novo access to such compounds has been investigated through a [4+2] heterocycloaddition route, previously validated in a model series. For this purpose, two new dienophiles, conveniently protected at the phenolic positions, were synthesized. From an extensive study of their reactivity towards a range of 4-hetero-substituted (“prosugar”) heterodienes, the expected heteroadducts
在
萘环上显示 1,5-双官能团的 C-
萘基糖苷可以氧化成
溴萘醌,是合成天然 C-芳基糖苷类似物的关键中间体。在该领域,糖修饰衍
生物具有特殊意义,但它们的合成具有挑战性。已经通过 [4+2] 杂环加成路线研究了对此类化合物的从头访问,之前已在模型系列中进行了验证。为此,合成了两种在
酚位置方便地受到保护的新亲二烯体。通过对其对一系列 4-杂取代(“原糖”)杂二烯的反应性的广泛研究,以可接受的产率立体选择性地获得了预期的杂加合物。
硼氢化/还原/氧化顺序的应用没有从还原的加合物中提供目标C-糖苷。讨论了底物的构象偏差对这种串联反应的负面影响。 (© Wiley-
VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)