Juglanaloids A and B are recently isolated natural products characterized by an unprecedented spiro bicyclic isobenzofuranone-tetrahydrobenzazepinone framework and a promising antiamyloid activity. Here reported is a straightforward convergent total synthesis of these natural products, which were obtained in high enantiomeric purity (94% and >99% ee for juglanaloids A and B, respectively) through an eight-step longest linear sequence, based on an efficient and reliable enantioselective phase-transfer-catalyzed alkylation step. Considering the interesting biological activity of juglanaloids, this convenient, highly enantioselective, flexible, and predictable synthetic strategy promises to be a powerful tool for accessing potentially bioactive spiro bicyclic phthalide-tetrahydrobenzazepinone derivatives.

中文翻译：

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(R)-核桃素 A 和 B 的灵活收敛对映选择性全合成：两种具有潜在阿尔茨海默氏病抑制活性的邻苯二甲酸酯螺生物碱

核桃素 A 和 B 是最近分离的天然产物，其特征在于前所未有的螺双环异苯并呋喃酮-四氢苯并氮杂酮框架和有前景的抗淀粉样蛋白活性。这里报道的是这些天然产物的直接收敛全合成，通过八步最长线性序列，基于高效和可靠的方法，以高对映体纯度（核桃素 A 和 B 分别为 94% 和 >99% ee）获得了这些天然产物。可靠的对映选择性相转移催化烷基化步骤。考虑到胡桃素类化合物有趣的生物活性，这种方便、高度对映选择性、灵活且可预测的合成策略有望成为获得具有潜在生物活性的螺双环苯酞-四氢苯并氮杂酮衍生物的有力工具。