One-pot divergent synthesis of 5-arylmethyl oxazoles and polyacenes from propargylic amides and arynes.

We report a sequential one-pot gold-catalyzed cyclization/aryne cycloaddition strategy that affords structurally diverse 5-arylmethyl oxazoles and substituted polyacenes from simple propargylic amides. Arynes are shown to engage the oxazoline products from gold catalysis via an ene reaction, with the resulting oxazoles trapping excess aryne in a cascade cycloaddition process to furnish epoxyacenes. Telescoping a subsequent deoxygenation reaction provides direct access to a range of polyaromatic hydrocarbon frameworks via a one-pot, three-stage transformation. This protocol is simple to perform, operates under mild reaction conditions and affords high levels of product selectivity through straightforward control of aryne stoichiometry.