Synthesis of o-Arylenedizinc Compounds and Their Synthetic Applications

在许多有机化合物中观察到在苯环的相邻位置具有两个不同侧链的芳烃的结构。构建这种结构的一种一般方法可以使用SE或SN型取代反应，使用合成的邻苯二阴离子、阳离子或1-阴离子2-阳离子的等价物作为苯并段，并使用适当的试剂。在本研究中，我们尝试合成邻芳基二锌化合物，并将其作为邻芳基二阴离子的合成代物用于合成不对称的1，2-二取代芳香化合物。然而，由于1，2-二碘芳烃的可获得性有限，类似的路线似乎不太适用于邻芳基二锌化合物的合成。然后，研究了邻芳基二锌化合物的新合成途径。也就是说，苯酚的区域选择性碘化，然后羟基的三氟化反应，得到了含有碘S的芳基三氟化物…在正位更多的代用品。通过芳基三氟化锌与锌粉的反应，以较高的产率得到了多种邻芳基二锌化合物。在以三(2，4，6-三甲氧基苯基)膦或三(邻-甲苯基)膦为配体的钯(0)催化剂存在下，当碘苯或苯甲酰氯等当量试剂用于反应时，两个可能的中心之间的一个亲电侧选择性地发生了形式SE反应，得到了高产率的芳基锌化合物。在生成的溶液中进一步添加第二试剂再次引发催化反应，以较高的产率提供不对称的1，2-二取代芳烃。首次通过邻溴碘苯与锌粉反应合成了一种新型的邻苯基1-阴离子2-阳离子的合成等价物邻溴苯基锌化合物，并将其应用于钯(0)催化的交叉偶联反应。它与亲电试剂如芳基卤化物或芳基卤化物连续处理，然后与亲核试剂如氰化钾、炔烃或芳基锌化合物反应，以良好的产率得到各种不对称的1，2-二取代芳烃。较少

Structures of arenes, possessing two different side chains at adjacent positions of benzene ring, are observed in numerous organic compounds. One general way to construct such structures might utilize SE or SN type replacement reaction using synthetic equivalents of o-phenylene dianion, dication, or 1-anion 2-cation as benzo segments with appropriate reagents. In this research, we tried to synthesize o-arylenedizinc compounds, intending to use them as the synthetic equivalent of o-arylene dianion in the synthesis of unsymmetrically 1,2-disubstituted arenes.We have already reported on the synthesis of o-phenylenedizinc compound. However, it appeared that similar route will be less effective for the synthesis of o-arylenedizinc compounds because of the limited availability of 1,2-diiodoarenes. Then, new access to o-arylenedizinc compounds was investigated. That is, regioselective iodination of phenols, followed by triflation of the hydroxyl group, affords aryl triflates containing iodo s … More ubstituent at ortho position. Various o-arylenedizinc compounds were obtained in good yields by the reaction of the aryl triflates with zinc powder.Next, the reaction of o-phenylenedizinc compound with electrophilic reagents was examined. When one equivalent of such reagent as iodobenzene or benzoyl chloride was applied to the reaction in the presence of palladium(0) catalyst containing tris(2,4,6-tri-methoxyphenyl)phosphine or tri(o-tolyl)phosphine as a ligand, formal SE reaction took place selectively at one electrophilic side between two possible centers to afford arylzinc compounds in high yields. Further addition of second reagents to the resulting solutions induce the catalytic reactions once again, providing unsymmetrically 1,2-disubsutituted arenes in good yields.For the first time, o-bromophenylzinc compound as a novel synthetic equivalent of o-phenylene 1-anion 2-cation was prepared by the reaction of o-bromoiodobenzene with zinc powder and was applied to the palladium(0)-catalyzed cross-coupling. Its consecutive treatment with electrophilic reagents like aryl halides or aryl halides and then with nucleophilic reagents like potassium cyanide, alkyne, or arylzinc compounds afforded various unsymmetrically 1,2-disubstituted arenes in good yields. Less