A new, non-hydrogenolytic synthesis of hexanitrohexaazaisowurtzitane (HNIW, 1) has been investigated. The treatment of hexabenzyhexaazaisowurtzitane (HBIW, 2) with potassium permanganate in acetic anhydride resulted in oxidative debenzylation and acetylation to give tetraacetyldibenzylhexaazaisowurtzitane (TADB, 3a) and other intermediates from the oxidation. Subsequent nitrosolysis and nitrolysis of these intermediates with 65% HNO3/NaNO2 and 70% HNO3/AN produced HNIW in fair yield.