chiral HPLC, contrary to the previous attempts by Staab et al. Racemization took place rapidly at room temperature, and the barrier to enantiomerization was determined to be 93.2 kJ mol–1 at 283 K. This energy barrier was rationally deduced with a mechanism involving rotations about the single and triple bond axes, as revealed by DFT calculations. A tetrahedrane intermediate resulting from a transannular