[PhSiO<sub>1.5</sub>]<sub>8,10,12</sub>as nanoreactors for non-enzymatic introduction of ortho, meta or para-hydroxyl groups to aromatic molecules
作者:Mozhgan Bahrami、Xingwen Zhang、Morteza Ehsani、Yousef Jahani、Richard M. Laine
DOI:10.1039/c7dt00373k
日期:——
the traditional electrophilic reactions provide selective functionalization at each position on the aromatic ring. Furthermore, halogenation serves as a starting point for the synthesis of two structural isomers of practical utility, i.e. in drug prospecting. The o-bromo and p-iodo compounds are easily modified by catalytic cross-coupling to append diverse functional groups. Thereafter, F−/H2O2 treatment
传统的电溴化沿用已久的“规则”:吸电子事业溴化选择性的取代基元的位置,而电子取代基的青睐邻位和对位溴化。相比之下,在[PhSiO 1.5 ] 8,10,12倍半硅氧烷中,笼子起着相当于CF 3的庞大的吸电子基团的作用。然而,在温和条件下进行溴化反应却没有催化剂,极大地促进了邻位取代。令人惊讶的是,没有催化剂的ICl碘化有利于(> 90%)对位取代[ p -IC 6 H 4 SiO 1.5] 8,10,12。最后,硝化和Friedel-Crafts酰化和磺酰化是高度间选择性的,> 80%。原则上,两种卤化形式与传统的亲电反应相结合,可在芳环的每个位置提供选择性官能化。此外,卤化用作合成两种具有实际用途的结构异构体的起点,即在药物勘探中。的Ô溴和p碘化合物易于通过催化交叉偶联追加多种多样的官能团改性。此后,F - / H 2 ö 2处理使Si-C键断裂,用OH代替Si。这代表了将羟基引入芳环的