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 ...