Diversity-oriented synthesis of chromone inden-1-one-fused cyclopentadienylides and C -acylated chromone adducts via allylic phosphorus ylides.

An organophosphine-controlled diversity-oriented synthesis of chromone inden-1-one-fused cyclopentadienylides and C -acylated 2-((chromone-3-yl)methylene)-indandiones is reported. Key attributes of the methodology are the in situ generation of an allylic P-ylide and subsequent regio- and chemoselective intramolecular cyclization reactions that preferentially result in the aforementioned chromone adducts.