Heterocyclic coupling reactions with alkenyl bromides

The Pd-catalyzed coupling reactions of alkenyl bromides with heterocyclic alkynes (40) under the above phase-transfer conditions have been employed to prepare a large number of heterocyclic alkyne derivatives, including some naturally occurring compounds (Scheme 28). The experiment conditions... 

Tin Derivatives. Indole, A-protected by the (trimethylsilyl)ethoxymethyl group, is alkenylated as a 2-stannane 27 with vinyl bromides (Scheme 14). The coupling also proceeds readily with complex heterocycles as exemplified with the structures 28 and 29. 3,4-Bis(tri-n-butyl)stannylfuran or the 3-monostannyl derivative is available by a Diels-Alder reaction between bis(tri- -butylstannyl)acetylene and 4-phenyloxazole. Either substrate, 30 or 31, undergoes alkenylation when reacted with tran -p-bromostyrene (Scheme 15).Pil... 

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