Base cleavage of epichlorohydrin polymers

Epichlorohydrin polymers cleave much more readily with organolithium compounds than do other poly(alkylene oxides). In dilute toluene solution (1–2%) at ?78°C, the cleavage of polyepichlorohydrin occurs as rapidly as BuLi is added. The end-groups formed are about equimolar amounts of hydroxyl and carbonyl with small amounts of acetylene ends. This same cleavage reaction but without acetylene ends can be obtained with NaOH or NaOCH₃ in dimethyl sulfoxide at 65°C. The carbonyl groups can be reduced with LiAlH₄ in tetrahydrofuran to give hydroxyl-ended polymers. A mechanism is presented for this unusual cleavage reaction.