Single‐Electron/Pericyclic Cascade for the Synthesis of Dienes

Abstract

The highly efficient and diastereoselective synthesis of E dienes has been accomplished through radical cyclization of bromoallyl hydrazones. This methodology has been further extended to generate these products through a one-pot condensation/radical cyclization/cycloreversion cascade from simple aldehyde starting materials in high yields (> 75 %) and high diastereoselectivities (> 95:5). Mechanistic investigations suggest that the cascade reaction proceeds through a cyclic diazene intermediate prior to the cycloreversion.Scheme 4. One-pot hydrazone formation followed by one-electron/ pericyclic cascade for the synthesis of dienes 4 d, 4 e, and 4 f. Angewandte Chemie 6343