Exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls proceeding via C-H activation pathway
Exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls proceeding via C-H activation pathway
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DOI：
10.1021/ja8006534
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发表时间：
2008-04-30
影响因子：
15
通讯作者：
Gevorgyan, Vladimir
中科院分区：
文献类型：
--
作者：
Chernyak, Natalia;Gevorgyan, Vladimir
钯催化的邻炔基联芳基的排他性 5-exo-dig 加氢芳基化的第一个例子已经得到证实。与报道的早期通过弗里德尔-克拉夫茨机制进行的碳环化相比，这种加氢芳基化可以有效地利用电子中性和缺电子芳烃进行，产生具有确定的双键立体化学的芴骨架。基于缺电子芳烃对环化的高反应性、分子间和分子内动力学同位素效应的高值以及环化的独特顺式选择性，人们提出了一种涉及C-H激活基序的机制用于这种转化。
The first example of the palladium-catalyzed exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls has been demonstrated. In contrast to the reported earlier carbocyclizations proceeding via the Friedel-Crafts mechanism, this hydroarylation efficiently proceeds with electron-neutral and electron-deficient arenes, producing fluorene frameworks with defined stereochemistry of the double bond. On the basis of the high reactivity of electron-deficient arenes toward cyclization, high values of inter- and intramolecular kinetic isotope effects, and the exclusive cis-selectivity of cyclization, a mechanism involving a C-H activation motif has been proposed for this transformation.