Alkynylboronates and -boramides in CoI- and RhI-Catalyzed [2+2+2] Cycloadditions: Construction of Oligoaryls through Selective Suzuki Couplings
Alkynylboronates and -boramides in CoI- and RhI-Catalyzed [2+2+2] Cycloadditions: Construction of Oligoaryls through Selective Suzuki Couplings
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DOI：
10.1002/ejoc.201100371
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发表时间：
2011-06-01
影响因子：
2.8
通讯作者：
Gandon, Vincent
中科院分区：
文献类型：
--
作者：
Iannazzo, Laura;Vollhardt, K. Peter C.;Gandon, Vincent
通过过渡金属催化的硼化炔的[2+2+2]环加成反应，然后与芳基卤化物进行Suzuki交叉偶联，制备了寡芳基化合物。乙炔基硼基频哪醇酯参与了所有研究类型的钴催化的[2+2+2]环加成反应（即，全分子间环三聚化、二炔-炔共环化和全分子内三炔环异构化）。由此产生的平台产生的线性和角叔和四芳基后，钯催化的交叉偶联。此外，首次开发了炔基萘硼酰胺的[2+2+2]环加成反应。这些衍生物可以在铑络合物催化下与二炔进行共环化反应。因为硼酰胺基团在Suzuki偶联条件下是无活性的，但可以容易地脱保护以提供活性基团，所以可以实现硼酸酯/硼酰胺取代的苯的迭代官能化。
Oligoaryls were prepared through transition-metal-catalyzed [2+2+2] cycloadditions of borylated alkynes, followed by Suzuki cross-couplings with aryl halides. Ethynylboryl pinacolate took part in cobalt-catalyzed [2+2+2] cycloadditions of all types investigated (i.e., all-intermolecular cyclotrimerization, diyne-yne cocyclization, and all-intramolecular triyne cyclo-isomerization). The resulting platforms gave rise to linear and angular ter- and quateraryls after Pd-catalyzed cross-coupling. In addition, the first [2+2+2] cycloadditions involving alkynyl naphthaloboramides were developed. These derivatives could be cocyclized with diynes in the presence of a rhodium complex as catalyst. Because the boramide group is inactive under Suzuki coupling conditions, but can be readily deprotected to afford an active one, an iterative functionalization of a boronate-/boramide-substituted benzene could be achieved.