Halopalladation/decarboxylation/carbon-carbon forming domino process: synthesis of 5-halo-6-substituted benzo[b]naphtho[2,1-d]furans.

A novel and general halopalladation/decarboxylation/carbon-carbon forming domino protocol is described for the synthesis of 5-halo-6-substituted benzo[b]naphtho[2,1-d]furans. The protocol represents the first example of trapping the sigma-vinylpalladium intermediate, generated from halopalladation of alkynes, by the decarboxylative coupling reaction.