A multistep single-crystal-to-single-crystal bromodiacetylene dimerization
A multistep single-crystal-to-single-crystal bromodiacetylene dimerization
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DOI：
10.1038/nchem.1575
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发表时间：
2013-04-01
期刊：
影响因子：
21.8
通讯作者：
Frauenrath, Holger
中科院分区：
文献类型：
--
作者：
Hoheisel, Tobias N.;Schrettl, Stephen;Frauenrath, Holger
堆积限制和官能团的精确放置是结晶状态下的有机分子经常显示出在溶液中观察不到的不寻常的物理或化学性质的原因。在这里，我们报告一个单晶到单晶二聚溴代乙炔，涉及异常大的原子位移，以及分裂和形成几个键。密度泛函理论计算支持的机制，其中的二聚化是由[2 + 1]光环加成有利于在晶体结构中的碳-碳短接触的性质。反应进行到理论转化率而不损失结晶度，并且它也以良好的产率在制备规模上进行。此外，它代表了第一条合成（E）-1，2-二溴-1，2-二乙炔基乙烯的合成途径，其可作为制备分子碳支架的合成中间体。我们的发现既扩大了单晶到单晶反应的范围，又突出了它们作为复杂转化合成工具的潜力。
Packing constraints and precise placement of functional groups are the reason that organic molecules in the crystalline state often display unusual physical or chemical properties not observed in solution. Here we report a single-crystal-to-single-crystal dimerization of a bromodiacetylene that involves unusually large atom displacements as well as the cleavage and formation of several bonds. Density functional theory computations support a mechanism in which the dimerization is initiated by a [2 + 1] photocycloaddition favoured by the nature of carbon-carbon short contacts in the crystal structure. The reaction proceeded up to the theoretical degree of conversion without loss of crystallinity, and it was also performed on a preparative scale with good yield. Moreover, it represents the first synthetic pathway to (E)-1,2-dibromo-1,2-diethynylethenes, which could serve as synthetic intermediates for the preparation of molecular carbon scaffolds. Our findings both extend the scope of single-crystal-to-single-crystal reactions and highlight their potential as a synthetic tool for complex transformations.