Diene synthesis - Communication 2. Study of diene condensations of p-benzoquinone and 1,4-naphthoquinone by the spectrophotometric method

Abstract

1. It was shown by the spectrophotometric method that, in the reactions of p-benzoquinone with cyclopentadiene, isoprene, and piperylene, the formation both of the mono adduct and of the bis adduct is preceded by the formation of intermediate compounds. In the case of isoprene and piperylene,reaction at room temperature stops at the stage of the formation of the molecular complex of the mono adduct with the diene. 2. The reaction of 1,4-naphthoquinone with cyclopentadiene passes through the stage of the formation of an intermediate compound. In solutions of 1,4-napthoquinone in isoprene and piperylene no absorption attributable to a complex was observed, possibly because the rate of conversion of the complex into the adduct exceeds the rate of formation of the complex. © 1960 Consultants Bureau, Inc.