Permanganate Oxidation of 4,7-Dihydro-1,3-dioxepins: A New Method for the Preparation of Bis[carboxymethyl] Acetals via Acetalisation with (Z)-2-Butene-1,4-diol - Nieuwenhuizen, M S; Kieboom, A P G; Van Bekkum, H (Synthesis, 1981)