Cubane derivatives, prismane

Extremely highly strained C-C framework compounds such as cyclopropane, tetrahedrane, cubane and prismane have been synthetic targets among organic chemists for a long time. Cyclopropane, tetrahedrane and cubane are highly symmetric compounds with three-fold axes. In 1964, Eaton and Cole performed the first synthesis of cubane. " In 1973, Kats and Acton reported the first production of prismane. In 1981, Eaton et al. reported the first production of pentaprismane. In 1978, Maier et al. successfully isolated tetrahedrane with three-fold tert-butyl substituents by photolysis of the corresponding 2-cyclopentadienone derivative. Tetrahedrane is an isomer of cyclobutadiene. 

It is indeed unfortunate that the authors of Reference 110 chose to study the dicarbomethoxy derivative and the authors of Reference 111 chose the monocarbomethoxy derivative. Had the degree of substitution been the same, then equation 40 could have been rewritten (i) substituted cubane + quadricyclane substituted homocubane + prismane. 

---