Tetra-t-butyltetrahedrane. Synthesis

The first genuine tetrahedrane synthesis was reported in 1978 by the Maier group the preparation of tetra-f-butyltetrahedrane, 5 [18]. This synthesis, which demanded astonishing persistence and experimental skill (the experimental details are reported in a 1981 paper [19]) is sketched here. 

This outline omits details, sometimes at first fmstrating and often baffling, of some reactions, particularly the introduction of the fourth t-butyl group into the cyclopentadienone, and the photochemical isomerization of tetra-/-butylcyclopent- 

After much effort, a shorter and higher-yield to 5 was developed. Conditions were found (eventually ) under which tetra-/-butylcyclopropenyldiazomethane lost nitrogen to give tetra-/-butyltetrahedrane by carbene insertion into the double bond [25, 26, 27]  

The term corset is apparently based on the idea that the restraining device resists (lateral ) motion, although Hopf, in his review of the tetrahedrane problem [28], assures us that a corset does not actually work in the same manner as the f-butyl groups of 5 [29]. For the effect to work, the groups must be so big that the steric 

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