Highly Regioselective Benzylic Deprotonation of Some (η
<sup>6</sup>
‐Tetralin)‐ and (η
<sup>6</sup>
‐
<i>trans</i>
‐Octahydroanthracene)Cr(CO)
<sub>3</sub>
Derivatives: Is the Regioselectivity Stereoelectronically Controlled?
作者:Thorsten Volk、Dirk Bernicke、Jan W. Bats、Hans‐Günther Schmalz
DOI:10.1002/(sici)1099-0682(199812)1998:12<1883::aid-ejic1883>3.0.co;2-#
日期:1998.12
nucleophile additions to (arene)Cr(CO)3 complexes, it was anticipated that those benzylic positions which are activated by an eclipsed CO ligand should be preferentially deprotonated (kinetically controlled). This (new) stereoelectronic model was corroborated by experiments using complexes rac-60 and rac-62, which were regioselectively deprotonated at the predicted position. In summary, it has been shown for
已经检查了许多构象受限的(芳烃)Cr(CO) 3 配合物的苄基去质子化的区域选择性,以确定立体电子效应是否在此类反应中起作用。配合物 rac-5、rac-6、rac-7、rac-8 和 rac-9 是由相应的 C2 对称配体(2,3-二取代反式-1,2,3,4-四氢萘和反式)非对映选择性合成的。 -1,2,3,4,4a,9,9a,10-八氢蒽衍生物)。由于 Cr(CO)3 络合引起的去对称化,所有四种苄质质子都可以通过 1H NMR 进行区分,并且在所有情况下都可以通过 H,H-COSY 光谱的组合和在两者处观察 H/D 交换来指定外位置(tert-BuOK/[D6]DMSO)。去质子化(正丁基锂)/氘化(D2O 或 CF3CO2D)实验表明,在 rac-5 和 rac-7 的情况下具有不可预见的区域选择性,而其他底物显示出低选择性 (rac-6) 或在这些条件下根本无法氘化 (rac-8、rac-9)。在