Phthalides are an important class of compounds owing to their role as the key structural motifs in bioactive natural products and pharmaceutical synthesis. C-H activation has become a promising strategy for preparation of phthalides due to its advantages of high efficiency and atomic economy compared with the traditional methods. In this paper, we summarized recent advances on synthesis of 3-substituted phthalides via C-H activation according to different transition metal catalytic systems.

Daldinins are a novel type of naturally occurring tricyclic heterocycles isolated from Daldinia concentrica. In this study, four daldinin A derivatives with different alkyl side chains were synthesized using the same synthetic protocol. Bioactivity tests first indicated that the daldinin A derivatives showed significant protection for endothelial cells against damage caused by high glucose. The derivative compound with three carbon atoms on the alkyl side exhibited the best effect.

para-Selective hydroxylation of alkyl aryl ethers is established, which proceeds with a ruthenium(ii) catalyst, hypervalent iodine(iii) and trifluoroacetic anhydride via a radical mechanism.

p-Alkoxy phenol (p-AOPs) compounds were obtained by one-step selective hydroxylation of alkoxyl-aryl ethers with the transition metal ruthenium(II) as catalyst and [bis(trifluoroacetoxy)iodo]benzene (PIFA) as oxidant. These p-AOPs could be easily converted to quinone monoacetals (QMAs) after dearomatization. Condensation of the QMAs with β-naphthols provided polycyclic benzofurans which have a wide application prospect. The protocol established in this paper offered a facile and reliable way for the synthesis of these important compounds. Keywords transition metal catalysis; regioselectivity hydroxylation; C-H activation; p-alkoxy phenol 对烷氧基苯酚(p-AOPs)是一个重要的结构单元, 该 结构或由其衍生得到的对烷氧基苯基醚结构广泛存在 于医药和有机合成化合物中, 也存在于许多活性天然产 物中(图 1). 此外, 对烷氧基苯酚去芳构化后得到的醌单 缩醛(QMAs), 进一步缩合反应能得到具有许多重要应 用的多环杂芳族化合物 [1] , 如具有双态发射特性的化合 物 [2] (图 2a)和分子工程原料 [3] (图 2b)等, 可为这类化合物 骨架的构建提供一条简洁高效的途径. 因此, 发展高效 便捷的对烷氧基苯酚类化合物的合成方法, 并探索其在 合成中的应用价值, 具有重要的意义, 也一直是有机合 成领域研究的热点之一 [4] .经典的对烷氧基苯酚的制备方法区域选择性 [5] 一般 不高, 或者要预先对底物进行其它官能化 [6] , 因此这些 制备方法存在着步骤较多、反应条件剧烈、底物适用范 围窄和产量低等局限性(Scheme 1).