Abstract

Possible synthetic routes to 4-bromo-1,1′:4′,1″-terphenyl and 4-methyl-1,1′:4′,1″-terphenyl have been studied. Stevens rearrangement of quaternary ammonium salts containing 3-phenylprop-2-en-1-yl and 3-(4-bromo- or 4-methylphenyl)prop-2-yn-1-yl groups gave 1-(4-bromophenyl)-N,N-dimethyl-4-phenylhex-5-en-1-yn-3-amine, 1-(4-bromophenyl)-N,N-diethyl-4-phenylhex-5-en-1-yn-3-amine, 1-(4-bromophenyl)-4-phenyl-N,N-dipropylhex-5-en-1-yn-3-amine, 1-[1-(4-bromophenyl)-4-phenylhex-5-en-1-yn-3-yl]piperidine, 4-[1-(4-bromophenyl)-4-phenylhex-5-en-1-yn-3-yl]morpholine, 1-[1-(4-methylphenyl)-4-phenylhex-5-en-1-yn-3-yl]piperidine, and 4-[1-(4-methylphenyl)-4-phenylhex-5-en-1-yn-3-yl]morpholine. Vacuum distillation of the resulting amines, by analogy with structurally related compounds, was accompanied by deamination with the formation of 4-bromo-1,1′:4′,1″-terphenyl and 4-methyl-1,1′:4′,1″-terphenyl in high yields. This transformation is a domino reaction involving β-elimination of secondary amine to form conjugated dienyne, electrocyclization of the latter to cyclic allene intermediate, and fast 1,3- or 1,5-hydride shift.

中文翻译：

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4-溴-1,1'：4'，1''-三联苯和4-甲基-1,1'：4'，1''-三联苯的合成

摘要

研究了生成4-溴-1,1'：4'，1''-联苯和4-甲基-1,1'：4'，1''-联苯的可能合成路线。含有3-苯基丙-2-烯-1-基和3-（4-溴-或4-甲基苯基）丙-2-yn-1-基的季铵盐的史蒂文斯重排得到1-（4-溴苯基）- N，N-二甲基-4-苯基己基-5-en-1-yn-3-胺，1-（4-溴苯基）-N，N-二乙基-4-苯基己基-5-en-1-yn-3-胺，1-（4-溴苯基）-4-苯基-N，N-二丙基己基-5-en-1-yn-3-胺，1- [1-（4-溴苯基）-4-苯基己基-5-en-1-yn-3-yl]哌啶，4- [1-（ 4-溴苯基）-4-苯基六（5-en-1-yn-3-yl）吗啉，1- [1-（4-甲基苯基）-4-苯基六（5-en-1-yn-3-yl）]哌啶和4- [1-（4-甲基苯基）-4-苯基己基-5-en-1-yn-3-基]吗啉。类似于结构上相关的化合物，对所得胺进行真空蒸馏，同时进行脱氨基反应，形成4-溴-1,1'：4'，1''-三联苯和4-甲基-1,1'：4' ，1”-三联苯的收率很高。这种转变是一个多米诺骨牌反应，涉及β-消除仲胺以形成共轭二烯，将后者电环化为环状亚丙基中间体，并快速发生1,3-或1,5-氢化物移位。