Oxetanes, which are four-membered-ring cyclic ethers of type 1, are important building blocks in medicinal and natural product chemistry.[1] Oxetanes are useful reagents that undergo ring-opening [2] or ring-expansion [3] reactions because of a large ring strain (ca. 25kcalmolÀ1)[4] and a high nucleophilicity of the O atom.[5] These derivatives react readily in the presence of Brønsted or Lewis acids to promote polymerization reactions.[6] ...
