Critical substructures in many bioactive molecules and natural products are ethers. They are typically synthesized through attack of a nucleophilic oxygen on an electrophilic carbon.

Rachel Willand-Charnley, Benjamin W. Puffer, and Patrick H. Dussault, University of Nebraska—Lincoln, USA, have demonstrated a new approach to synthesize spirocyclic ethers, aryl ethers, and various oxacycles including oxetanes.

They generated carbanions via chemoselective metal-heteroatom exchange or deprotonation. An intramolecular reaction of dialkyl peroxides with the carbanios leads to cyclic ethers. Applied in tandem with C−C bond formation, the strategy enables a one-step annelation to form oxaospirocycles.

• Oxacycle Synthesis via Intramolecular Reaction of Carbanions and Peroxides,
  Rachel Willand-Charnley, Benjamin W. Puffer, Patrick H. Dussault,
  J. Am. Chem. Soc. 2015.
  DOI: 10.1021/ja5026276