1,1′-Biindenes 2, conveniently prepared from indenyllithiums by treatment with copper(II) chloride, are quantitatively isomerized to the corresponding 3,3′-biindenes 3 by heating in triethylamine/pyridine. Both d, l and meso isomers of 2 react to form 3, the rate of reaction of the meso form, however, is substantially faster.
1,1′-联
茚 2 是通过
氯化
铜(II)处理从
茚二
噻吩制备的,在
三乙胺/
吡啶中加热定量异构化成相应的 3,3′-联
茚 3。 2 的 d、l 和中间异构体都会发生反应生成 3,但中间异构体的反应速度要快得多。