A simple, direct, high-yield Friedel-Crafts synthesis of highly chlorinated, overcrowded αH-aryl, αH-diaryl, and αH-triarylmethanes is described. The latter compounds are most valuable chemical precursors of inert free radicals, which are frequently obtained through otherwise cumbersome, medium-to-low-yield aromatic chlorination of triphenylmethane derivatives. The condensation is performed with aluminium chloride at temperatures ranging from 70 to 160°C. The substrate is a benzene with all its hydrogens flanked by two ortho chlorines. The alkylating component is chloroform, αH-heptachlorotoluene (2a) or αH-undecachlorodiphenylmethane (3a). For comparison, the condensation with a few non-sterically-hindered substrates has also been performed.
描述了一种简单、直接、高产率的Friedel-Crafts合成反应,用于合成高度
氯化的拥挤型αH-芳基、αH-二芳基和αH-三芳基
甲烷。这些化合物是惰性自由基的最有价值的
化学前体,通常通过繁琐的中到低产率的芳香
氯化三
苯甲烷衍
生物获得。该缩合反应在70至160°C的温度下使用
氯化
铝进行。底物是一个
苯环,其所有
氢原子旁边都有两个邻位
氯原子。烷基化组分为
氯仿、αH-
七氯甲苯(2a)或αH-十
氯二
苯甲烷(3a)。为了进行比较,也对一些非立体障碍底物进行了缩合反应。