[kbob]

I think that well-known routes to cubane may be used to azacubane too with little modifications.
http://www.chm.bris.ac.uk/webprojects2004/hook/synthesis/index.html

First and second routes can be used if we started with 3-Aza-5-bromo-2,4-cyclopentadienone (not very stable combound) and bromocyclopentadienone or its acetale.
Third route can be used if we started with Tri-tert-butylazete and 2,5-dibromo-1,4-benzoquinone.
And Third route can be used again if we started with cyclobutadiene and 2,5-dibromopyridine-3,6-dione.