Cyclisation of Ethylene Dinitramine

In my first Doctoral dissertation available on 4shared.com, I attempted to cyclise ethylenedinitramine by condensation with dimethylamino dichloroborane, but failed to obtain the expected N,N dinitro diazaboracyclopentane,as proved by mass spectrometry.
Only a boronate anion with four ethylenedinitramine ligands was obtained, as proved by infrared spectrum (3 new bands near 10µ) and microanalysis(1,38% boron).

This is consistent with the high electrodeficiency of boron and difficulties to nitrate boron compounds.

Someone should have attempted similar reactions, such as condensation of phosgene with ethylenedinitramine.Do you have any informations on such reactions?Thanks.