Synthesis of o-Arylenedizinc Compounds and Their Synthetic Applications

芳烃的结构，在苯环的相邻位置具有两个不同的侧链，在许多有机化合物中观察到。构建这种结构的一种一般方法是利用SE或SN型替代反应，使用合成的邻苯二甲酸乙二醇酯、二甲二甲酸乙二醇酯或1-阴离子2-阳离子作为苯并段，并使用适当的试剂。在本研究中，我们尝试合成邻芳烯二锌化合物，打算将其作为邻芳烯二离子的合成等价物用于不对称1,2-二取代芳烃的合成。我们已经报道了邻苯二锌化合物的合成。然而，由于1,2-二碘芳烃的可用性有限，类似的方法对于邻芳二锌化合物的合成似乎不太有效。然后，研究了邻芳基二锌化合物的新途径。也就是说，苯酚的区域选择性碘化，接着是羟基的三氟化，在邻位上提供含有碘的芳基三氟化盐。用三氟化芳酯与锌粉反应，得到了收率较高的邻芳二锌化合物。其次，考察了邻苯二锌化合物与亲电试剂的反应。当在钯(0)催化剂（含三（2,4,6-三-甲氧基苯基）膦或三（o-甲苯基）膦作为配体）存在的情况下，将碘苯或苯酰氯等价物应用于反应时，在两个可能的中心之间的亲电侧选择性地发生形式SE反应，以获得高产量的芳基锌化合物。在生成的溶液中进一步加入第二试剂，再次诱导催化反应，得到高产率不对称的1,2-二取代芳烃。以邻溴碘苯和锌粉为原料，首次合成了一种新型的邻溴苯锌化合物，作为邻苯1-阴离子2-阳离子的合成物，并应用于钯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、炔或芳基锌化合物连续处理，得到各种不对称的1,2-二取代芳烃，收率很高。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