Convergent Assembly of Polycyclic Ethers via Acyl Radical Addition to Unactivated Enol Ether

A new convergent strategy for assembling 6/6- and 6/7-fused ether ring systems was developed. The key features in our method include Ag-promoted facile formation of chemically labile enol ether from O,S-acetal and addition of an acyl radical to unactivated enol ether to cyclize a six- or seven-membered ether ring.