Catalytic ethenylation reaction of phenol using SnCl4

[GRAPHICS] Ethenylation reaction of phenol with silylethyne at the o-position is catalyzed by the SnCl4-BuLi reagent. While turn over numbers (TONs) in the reactions of m- or p-substituted phenols are 3 to 4, those for o-substituted phenols are 8 to 9.