Aryl nitrones, reaction with copper

Another interesting cascade involving nitrones is the copper catalyzed reaction with alkynes to produce p-lactams that was originally reported by Kinugasa (72CC466). Stoichiometric amounts of copper(I) phenylacetylide (61) react with various aryl nitrones 62 in pyridine to give p-lactams 63 in 50-60% yield (equation (2)). In each case, only the czs-lactams were isolated. 

On the other hand, Suzuki and co-workers have demonstrated that copper(I) species can promote the reaction of vinyl halides with terminal alkynes without the need for a palladium catalyst however, as in the Castro reaction, a stoichiometric amount of copper salt is needed. By contrast, Miura and coworkers found that aryl and vinyl iodides smoothly react with terminal alkynes in the presence of a catalytic amount of copper iodide using potassium carbonate as base when an appropriate amount of triphenylphosphine is added. Pyridine or 1,2-bis(diphenylphosphino)ethane (dppe) have been used as ligands in the case of Cul-catalyzed reaction of terminal alkynes with nitrones. ... 

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