Synthesis of Endiynes

In general, enediynes are prepared by a Pd/Cu-mediated cross-coupling reaction of vinyl dihalides or analogs with terminal acetylenes under standard conditions in good to excellent yields. In the synthesis of endiyne 63, acceptable monosubstitution of a vinyl dihalide 62 can be achieved by using a large excess of the dihalides over the alkyne (Scheme 24). 

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