Direct Metalation of 1,3,5,7-Tetranitrocubane with Amides of Tin and Lead. Preparation and Chemistry of o-Nitrostannanes and o-Nitroplumbanes in the Cubyl Series(1)

Trialkyltin and trialkyllead amides react directly and remarkably easily with 1,3,5,7-tetranitrocubane to form mono- to tetrakis(trialkyltin)- and -(trialkyllead) tetranitrocubanes. These are all stable compounds. The X-ray crystallographic properties of some are given. The (trialkylstannyl)cubanes react with electrophiles such as bromine with unexpected cleavage of alkyltin bonds rather than cubyl-tin bonds. On the other hand, the (trialkylplumbyl)cubanes do ultimately undergo cubyl-lead bond cleavage. This provides a useful way to achieve substitution on the cubane nucleus and provides access to compounds such as 1,3,5,7-tetrabromo-2,4,6,8-tetranitrocubane. The lead derivatives of tetranitrocubane are also useful for making 1,2,3,5,7-pentanitrocubane and 1,2,3,4,5,7-hexanitrocubane.