Tetra‐<i>tert</i>‐butylcyclopentadienone

Abstract

The stable tetrahedrane derivative (3)—the very first alkyl-substituted tetrahedrane—has now been synthesized photochemically from the cyclopentadienone (1). 1H-NMR, 13C-NMR, mass, and IR spectra, as well as the reversible isomerization to (2), are compatible with the tetrahedrane structure. The unexpected stability of the compound is attributed to substitution of all four corners of the skeleton with bulky groups.—The starting material (1), which is also new could only be prepared under “forbidden conditions”.