Aryliminodimagnesium Reagents. XV. Condensation with Nitrobenzene. Formation of Unsymmetrical Azobenzenes Favored by Long-Chain<i>p</i>-Alkoxy-Substituted Reagents
作者:Masao Okubo、Koji Matsuo、Akira Yamauchi
DOI:10.1246/bcsj.62.915
日期:1989.3
In the reaction of p-MeC6H4N(MgBr)2 with p-alkoxynitrobenzene, no effect of alkoxyl chain length on the relative yields of azoxy and azo products was observed. In contrast, in the reaction of p-alkoxy-C6H4N(MgBr)2 with p-nitrotoluene, C12- and C18-alkoxyl chains led to the corresponding unsymmetrical azobenzenes in unexpectedly high yields. This result, arising from efficient condensation and deoxygenation processes, was explained in terms of cooperation of reagent molecules through their aggregation assisted by a novel tying effect of their long chains.
Cooperation of aryliminodimagnesium molecules: Deoxygenation of azoxyarenes by mono- and bifunctional reagents in comparison with that by phosphorus(III) reagents
proposed. This unfamiliar concept for reactions of magnesium reagents was studied further. Supporting evidence was obtained from the retarding effect of trimethylene chains of nitro [3.3] metacyclophanes and the derived azoxy [3.3] metacyclophanes and also from the effect of the length of bis-IDMg's central α,ω-polymethylenedioxy chain appropriate for azoxy deoxygenation. By comparison with deoxygenation