Reaction of 4-alkoxy-2-chloro-l-butanols (1) and their acetates II with bases depends on the base and reaction conditions employed and affords complex mixtures of fragmentation products or mixtures of 4-alkoxy-2-buten-l-ols (III) and 4-alkoxy-3-buten-l-ols (IV) or almost pure trans-IV. Hydrogenolysis of 2,5-dihydro-2,5-dimethoxyfuran (V) by chloroalane leads to trans--4-methoxy-2-buten-l-ol (trans-IlIa). Vinyl ethers IV undergo an acid-catalyzed cycIisation to the corresponding 2-alkoxytetrahydrofurans VI.We have described 1 a simple method which affords high yields of 4-alkoxy-3-chloro--l-butanols (1) and their acetates 2 II. The present communication describes our studies of the behaviour of compounds I and II in their reactions with bases.Reactions of y-halohydrins (or 1,3-diols) or their esters with aqu~ous potassium hydroxide 3 • 4 or potassium tert-butoxide 5 are often used in the synthesi~ of oxetanes. Compounds I can be looked upon as r-chlorohydrins, as well as ~-chloro ethers, the latter suggesting that the chlorine atom will resist considerably a nucleophilic substitution 6 • In actual fact, reaction of both alcohols I and esters II with aqueous potassium hydroxide at 373 K afforded products of hydrolysis and/or elimination in about 80% yields and it was not possible to prove the formation of the corresponding oxetanes. The mixtures of elimination products were separated only on the anIytical scale using an efficient capillary column. We found that these mixtures consist invariably of four components, two of which represent about 85 -90% of the mixture and their ratio is 1 : 1 to 1 : 2 depending on the starting compound. The elementar analyses of the mixtures corresponded exactly to the values calculated for alkoxybutenols. Also their 1 H-NMR, spectra, simplified by working with hexadeuteriodimethyl sulfoxide solutions 7 and by using shift reagents, indicated that the main portions of the mixtures are always the corresponding trans-4-alkoxy-2-buten-l-ols (trans-III) together with trans-4-alkoxy-3-buten-l-ols (trans-IV). As shown in Table I, the 1 H-NMR studies involved the determination of the coupling constants between olefinic protons S and comparison of calculated 9 and found chemical shifts of these protons.

Die Alkohole (I), ebenso ihre Essigsäureester, geben beim Erhitzen mit KOH und wenig Wasser auf 373 K Gemische der Alkoxybutenole (II) und (III), beim Erhitzen auf 448 Kdagegen ausschließlich die Butenole (III) [in die auch die (II)/(III)‐Gemische bei 448 K übergehen].