Eaton PE,
Cole T.
The University of Chicago, USA
Cubane.
J. Am. Chem. Soc. 1964;
86: 3157-3158
Key words
cubanes - hydrocarbons - strained structures
Significance
Cubane (9) is a highly strained hydrocarbon in which eight carbon atoms are arranged at the
corners of a cube, adopting unusually 90° bonding angles. Before it was first synthesized
in 1964 by Eaton and Cole, researchers believed that such cubic carbon-based molecule
would be too unstable to exist. Initially, cubane was considered just a laboratory curiosity of interest only to
academics, however, over time this remarkable hydrocarbon and derivatives have found
applications in controlled energy storage, the explosives industry, pharmaceuticals,
and polymer science.
Comment
The classic synthesis of cubane starts from 2-cyclopentenone and consists of fifteen
discrete steps with an overall yield of about 5%. There are three key synthetic elements:
(a) the highly endo-selective Diels–Alder reaction of 2-bromocyclopentadienone (1) generated in situ, producing the endo-dimer 2 (J. Am. Chem. Soc.
1964, 86, 962); (b) the [2+2] photocyclization of 3, obtaining 4; and (c) the double Favorskii ring contraction of the cage diones 4 and 7, producing 5 and 8, respectively. Nowadays, the chemistry of cubane is well developed and it can be
easily obtained on a multi-gram scale (see Review below).
Review
K. F. Biegasiewicz, J. R. Griffiths, G. P. Savage, J. Tsanaktsidis, R. Priefer Chem. Rev. 2015, 115, 6719–6745.
