It is well-known that aryl cyclopropanes favour a bisected conformation to enable overlap between the -Walsh orbitals and the * of the benzene ring. 20 Another effect of this interaction is also the weakening of the C-C bond and favour ring-opening. With one ortho group, a low energy bisected conformer is still available. However, when a second ortho group is present, strong steric interactions with the cyclopropane cannot be avoided anymore. Therefore, the usually less favoured perpendicular conformation becomes lower in energy. In this conformation, there is nearly no effect of the benzene ring on the strength of the C-C bonds. In contrast, one may envision a weakening interaction between the  system of the benzene and the * orbital of the C-H bond, favouring deprotonation/H abstraction. Of course, care has to be taken with this simple conformational analysis of the starting material, and future studies will focus on computations involving radical cation II and the transition states of the proposed pathways a and b. Scheme 4 Speculative mechanism for the C-C oxyalkynylation and the C-H alkynylation reactions (A) and conformational analysis of arylcyclopropanes (B).