Oxacycle Synthesis via Intramolecular Reaction of Carbanions and Peroxides

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