Enediynes stannylcupration

The reaction has been incorporated into a synthetic approach to enediynes [77]. Structural and mechanistic studies by Oehlschlager established the reversibility of these stannylcupration reactions [25cj. Although the resultant vinylcopper reagents were thermodynamically favored, crossover experiments found facile ligand exchange processes. Efforts to control the regiochemistry of the addition were met... 

The syn stereoselectivity exhibited the stannylcupration of alkynes is used for the synthesis of stannylated enynes 139 which could be readily transformed to the desired enediynes [67] [Eq. (46)]. 

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