Novel Synthetic Method of 2, 6-Naphthalenedicarboxylic Acid

为了开发一条合成2，6-萘二甲酸的新路线，对钯催化环羰基化反应进行了深入研究。主要研究结果如下：1. 2-甲基-3-（对甲苯基）烯丙基乙酸酯在NEt_3、Ac_2O和催化量的PdCl_2（PPh_3）_2存在下环羰基化得到1-乙酰氧基-3，7-二甲基萘。苯磺酸盐在Pd（OAc）_2-dppb催化下氢解得到2，6-二甲基萘，后者氧化为1是已知的。因此，这些反应完成了一个新的路线1。研究了5-乙酰氧基-1-萘甲酸的环羰基化合成及其与4-乙酰氧基苯甲酸共聚物的物理性能.通过3-呋喃基、3-噻吩基、3-吡咯基和3-吲哚基乙酸烯丙酯的环羰基化反应，分别高产率地得到了乙酰氧基苯并呋喃、乙酰氧基苯并噻吩、乙酰氧基吲哚和乙酰氧基咔唑。通过从异百里酚合成大麻呋喃证明了该反应的合成效用。3，3-二芳基烯丙基乙酸酯的环羰基化得到对芳基取代的稠合乙酸苯酯，其中环化选择性地发生在更富电子的环上。这一结果表明，该反应涉及分子内亲电攻击的酰基配位钯的芳环. 2，4-二乙酸苯酯经环羰基化反应得到乙酸苯酯，产率较高.该反应提供了一条合成取代苯酯（包括3，5-或2，3-二取代苯酯）的通用路线，而这些取代苯酯是通过苯酚的常规亲电取代反应难以得到的。

With the aim of developing of a novel route to 2, 6-naphthalenedicarboxlic acid 1, the palladium catalyzed cyclocarbonylation was extensively studied. The major results are as follows :1. Cyclocarbonylation of 2-methyl-3-(p-tolyl)allyl acetate in the presence of NEt_3, Ac_2O, and a catalytic amount of PdCl_2(PPh_3)_2 gave 1-acetoxy-3, 7-dimethylnaphthalene in a good yield, which was converted to the corresponding benzenesulfonate. Hydrogenolysis of the benzenesulfonate catalyzed by Pd(OAc)_2-dppb afforded 2,6-dimethylnaphthalene, whose oxidation to 1 is well-known. Therefore these reactions accomplish a novel route to 1. Synthesis of 5-acetoxy-1-naphthoic acid via the cyclocarbonytlation and physical properties of its copolymer with 4-acetoxybenzoic acid were also investigated.2. Acetoxybenzofurans, acetoxybenzothiophenes, acetoxyindoles, and acetoxycarbazoles were obtained in high yields by the cyclocarbonylation of 3-furyl, 3-thienyl, 3-pyrrolyl, and 3-indolylallyl acetates, respectively. The synthetic utility of the reaction was demonstrated by the synthesis of cannabifuran from isothymol.3. Cyclocarbonylation of 3,3-diarylallyl acetates afforded p-aryl-substituted fused phenyl acetates where the cyclization occurred selectively on the more electron rich ring. This result suggests that the reaction involves the intramolecular electrophilic attack of the acyl group coordinated by palladium on the aromatic ring.4. Cyclocarbonylation of 2, 4-pentadienyl acetates was revealed to give phenyl acetates in good yields. This reaction provides a versatile and general synthetic route to substituted phenyl esters including 3, 5- or 2, 3- disubstituted ones, which are hardly obtainable by conventional electrophilic subs titution reactions of phenol.