Reactions of 1-Naphthols with .PI.-Acceptor p-Benzoquinones: Oxidative Aryl Coupling vs. Non-Oxidative Electrophilic Arylation
作者:Tetsuya Takeya、Hiromu Kondo、Tsuyoshi Otsuka、Hirohisa Doi、Iwao Okamoto、Eiichi Kotani
DOI:10.1248/cpb.53.199
日期:——
We investigated the reactions of various 1-naphthols (NPOHs; 1) with p-benzoquinones (Qs), such as 1,4-benzoquinone (BQ) and p-chloranil (CA), as π-electron acceptors. With electron-rich NPOHs 1a—c, oxidative biaryl coupling and subsequent dehydrogenation reaction took place selectively to give the corresponding 2,2′-binapthyl-1,1′-quinones 3a—c in excellent yield. In the case of electron-deficient NPOHs 1e, f, two different types of reactions occurred in the presence of SnCl4 and ZrO2 under similar conditions: SnCl4 mediated oxidative dimerization and trimerization of NPOH, while ZrO2 promoted electrophilic arylation of Qs with NPOH. The resulting products 3 would be useful synthetic intermediates for naturally occurring diosindigo B, biramentaceone and violet-quinone.
我们研究了各种 1-萘酚(NPOHs;1)与对苯醌(Qs)(如 1,4-苯醌(BQ)和对氯苯胺(CA))作为 π 电子受体的反应。对于富电子的 NPOH 1a-c,可选择性地进行氧化双芳基偶联和随后的脱氢反应,从而得到相应的 2,2′-联萘-1,1′-醌 3a-c,收率极高。对于缺电子的 NPOH 1e、f,在氯化锡和二氧化锆存在的类似条件下发生了两种不同类型的反应:SnCl4 介导了 NPOH 的氧化二聚化和三聚化,而 ZrO2 则促进了 Qs 与 NPOH 的亲电芳基化。由此产生的产物 3 将成为天然存在的双靛蓝 B、双蒽酮和紫罗兰醌的有用合成中间体。