Synthesis of hexacyclo[5.4.1.02,6.03,10.04,8.09,12]dodecane‐5,11‐dione and its conversion to di‐, tri‐, and tetranitro‐1,3‐bishomopentaprismanes

Abstract

AbstractSulfenylation of the dianion of dimethyl tetracyclo[7.2.1.04,11.06,10]dodeca‐2,7‐diene‐5,12‐dicarboxylate (9) with dimethyl disulfide delivered the exo,exo‐bis(methylthio) derivative 10a. Subsequent saponification and oxidative decarboxylation resulted in transformation to tetracyclo[7.2.1.04,11.06,10]dodeca‐2,7‐diene‐5,12‐dione (4). Upon photolysis of the bisketal 11 of this pivotal intermediate, arrival at the doubly functionalized 1,3‐bishomopentaprismane 12 was achieved. Following acidic hydrolysis to give the title compound 5, elaboration of three dinitro (14 – 16), two trinitro (20, 21), and a tetranitro derivative (22) was accomplished. The configurational assignment to the first four products was achieved by means of 1H NMR spectroscopy and an X‐ray crystal structure analysis of 21. The stereochemistries of the nitro‐substituted cage molecules are discussed in terms of the mechanism of their formation and their densities, many of which are markedly enhanced. The structural features of the tetranitro‐bishomopentaprismane 22 have also been elucidated by X‐ray methods.