Cage peroxides having planar bridgehead nitrogen atoms

Three new cage peroxides, 1,6-diaza-3,4,8,9-tetraoxabicyclo[4.4.2]dodecane (3a),1,6-diaza-3,4,8,9-tetraoxa-11methylbicyclo[4.4.2]dodecane (3b), and 1,6-diaza-3,4,8,9-tetraoxatricyclo[4.4.2.411,12]hexadecane (4), have been prepared by reaction of 1,2-diaminoethane, 1,2-diaminopropane, and trans-1,2-diaminocyclohexane, respectively, with formaldehyde and hydrogen peroxide in aqueous acidic solution. Their structures have been established by X-ray diffraction, and show the bridgehead nitrogen atoms to be predominantly sp2 hybridized. The structures accord with 1H and 13C NMR spectra. Variable temperature NMR studies show that the diperoxide 3a begins to undergo rapid inversion (on the NMR time scale) at about 303 K; up to 370 K the diperoxides 3b and 4 show no conformational change.