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Abstract

We found a novel ring-expansion reaction of 1,3-dioxacycloheptane with ethylene oxide to form 1,4,7,10-tetraoxacyclotetradecane. The reaction is thought to be composed of the following three steps: first, formation of an active intermediate from 3 mol of ethylene oxide and 1 mol of 1,3-dioxacycloheptane; second, elimination of formaldehyde from the intermediate; and finally, cyclization to form 1,4,7,10-tetraoxacyclotetradecane. The relation between the ring size and the ring strain energy is thought to be deeply involved in a significant factor in this novel reaction.