A general and efficient copper(I)-catalyzed cross-coupling and heterocyclization reaction of terminal alkynes and b-iodo-a,b-unsaturated acid derivatives has been developed under very mild conditions. This method provides easy access from good to excellent yields of a variety of 5-ylidenebutenolides and 3-substituted isocoumarins with excellent regioand stereoselectivity. This procedure does not require the use of any expensive supplementary additives, and is palladium-free.

Palladium-catalyzed stereoselective annulation of a functional vinylstannane by acyl chlorides gives the corresponding alpha-pyran-2-ones in good yields. This annulation most probably proceeds through a Stille reaction/cyclization sequence.

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