Synthesis of tri- and tetraynes using a butadiynyl synthon.

Using a one-pot protocol, triynes and tetraynes are formed from the reaction of a dibromovinyl triflate and a terminal alkyne under palladium-catalyzed cross-coupling conditions.

Synthesis and derivatization of ethynyl alpha,alpha-dibromomethyl ketones: formation of highly functionalized vinyl triflates.

[reaction: see text] We describe the synthesis of alpha,alpha-dibromomethyl ynones (8) and their subsequent derivatization to vinyl acetates (10). These vinyl acetates feature a 1,1-dibromo-olefin moiety, which is readily exploited in palladium-catalyzed Sonogashira, Stille, and Suzuki cross-coupling reactions with alkynes, stannanes, and boronic acids, respectively. A novel one-pot process then directly converts the resulting vinyl acetates 11-13 to the vinyl triflate derivatives 14a-j.