Oxymetallation. Part 11. Synthesis of cyclic secondary alkyl peroxides via the peroxymercuration of α,ω-dienes

Abstract

Six cyclic peroxides of the form [graphic omitted] [X = HgCl (1), H (2), or Br (3); n= 1 (a) or 2 (b)] have been prepared in high yield via the reaction of penta-1,4-diene or hexa-1,5-diene with hydrogen peroxide and mercury(II) nitrate. The new compounds are identified by 1H and proton-decoupled 13C n.m.r. spectroscopy and additionally by mass spectrometry where X = H or Br; compound (1a) isomerises to a β-oxo-alcohol when dissolved in pyridine. The 1,2-dioxacyclopentanes are obtained as approximately equimolar mixtures of cis-and trans-isomers whereas the 1,2-dioxacyclohexanes contain about three times as much trans- as cis-isomer. The configurations are assigned on the basis of 13C and 1H n.m.r. chemical shifts and variable-temperature n.m.r. spectra.