70411-98-2Relevant academic research and scientific papers
Simple Enols. 5. (Z)- and (E)-1-Hydroxy-1,3-butadiene
Capon, Brian,Guo, Bozhang
, p. 5144 - 5147 (2007/10/02)
(Z)- and (E)-1-hydroxybutadiene have been generated from their trimethylsilyl derivatives in slightly acidic aqueous acetonitrile and CH3OH-DMSO mixtures and characterized by NMR spectroscopy.The kinetics and products of ketonization of both dienols have been investigated.In aqueous solution they yield mixtures of (E)-2-butenal and 3-butenal whose proportions depend on pH.Analysis of the variation of product composition with pH indicates that (E)-1-hydroxybutadiene yields 90.1, 28.0, and 44.7percent of (E)-2-butenal in the H3O+, H2O, and HO--catalyzed reactions, whereas (Z)-1-hydroxybutadiene yields 69.8, 17.2, and 19.6percent.It is suggested that transmission of positive charge to the oxygen in the transition state for protonation at the 4-position is more efficient with the E than with the Z isomer, possibly because it is easier for the former to attain a planar conformation.No evidence was found for a mechanism that involves a cyclic transition state for the spontaneous ketonization of (Z)-butadienol.
