Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

This functional group is produced in the second step of the Darzens condensation and can be synthesized enantioselectively using a manganese-salen complex as a catalyst or a combination of titanium tetraisopropoxide and diethyl tartrate in reactions named for Jacobsen and Sharpless. Reaction with tungsten reagents and triphenylphosphine will result in elimination to produce alkenes; in the inverse reaction, a butterfly mechanism is hypothesized this functional group's formation from the reaction of a peroxyacid with an alkene. It may also be produced from a halohydrin via an intramolecular Williamson reaction. FTP name this highly strained functional group, a three-membered cyclic ether.
Science