DMAP-Catalyzed Annulation Approach for Modular Assembly of Furan-Fused Chromenes.

With a tandem DMAP-catalyzed reaction between -AQM, in which it is generated in situ from propargylic amine, and acyl carbene surrogate (from pyridinium ylide), a variety of polyarylated chromenes are assembled in good yields. This process does not require transition-metal catalyst and exhibits easy manipulation of the arene group and good functional group compatibility, particularly the -Br group which can be further transformed to other functionalities by cross-coupling reactions. The modular feature of -AQM substrates and the simple operation procedures add further advantages to this synthetic method.