The preparation of 3-heteroatom-substituted oxetanes by the yield, is possible. Since the oxetane formation proceeds stePaterno-Buchi reaction, and their application in synthesis are reoselectively, diastereomerically pure products are readily reviewed. 3-Oxetanols and 3-aminooxetanes are the two accessible, which can then be used in further transformamost important oxetanes in this respect. By tuning the elec-tions. To this end, regioselective ring-opening reactions have tronic properties of the enol and enamine substrates, a SUC-been developed, some of which will be discussed in this accessful photocycloaddition to carbonyl compounds, with high count.