Catalytic Multisite-Selective Acetoxylation Reactions at sp vs sp C-H Bonds in Cyclic Olefins.

The first Pd-catalyzed multisite-selective acetoxylation reactions are disclosed at an unactivated alkene sp C-H bond versus secondary allylic sp C-H bond in cyclic olefins via the modulation of directing groups. The different directing groups overcome the key challenge in differentiating C-H bonds and provide a new controlling approach for site-specific C-H activation. A wide variety of substrates are readily acetoxylated under operationally simple conditions. Mechanistic studies suggest that different Pd (IV) intermediates were involved in the multisite-selective acetoxylation reactions.