Composés Oléfiniques et Acétyléniques. IV. Nouvelles Synthèses du 1,3,5‐Hexatriene; Électrodimérisation de L'Acroléine sur un Couple Zinc‐Cuivre

The electrodimerisation of acroleine on a zinc‐copper couple in the presence of acetic acid gives 1,5‐hexadiene‐3,4‐diol 5 in 76% yield, the ratio meso/dl being 60/40. Gas chromatographic analysis of the reaction mixture reveals the presence of threo‐ and erythro‐1‐hexene‐3,4‐diol and of the mono‐ and di‐acetates (meso/dl) of 4, especially when large quantities of acetic acid are used. Optimum conditions are described in order to minimize these side‐reactions. Starting from 4, two new routes to 1,3,5‐hexatriene 1 has been developped, namely by treating the bistosylate derivative of 4 with sodium iodide in 2‐(2‐ethoxy‐ethoxy) ethanol (adaptation of Linstead's reaction) and by a modification of Corey's method, where 4 is treated with N′, N′‐thiocarbonyl‐diimidazole and the resulting cyclic thiocarbonate decomposed in triphenylphosphite. Hexatriene is obtained respectively in 52 and 47% overall yield, the cis/trans ratios being 10/90 and 20/80. Although these reaction schemes appear to be non‐stereospecific, they constitute two new valuable methods to cis‐1,3,5‐hexatriene. Copyright © 1974 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe