In the presence of 5 mol% Pd(OAc)2, 1 equiv. of norbornene, and K2CO3, the reaction of 4-iodo-2-quinolones with tertiary o-bromobenzylic alcohols produced the desired benzopyran-fused 2-quinolones in moderate to high yields.

The palladium‐catalyzed reaction of 4‐iodo‐2‐quinolones with activated alkynes was investigated. Cyclopenta[de]quinoline‐2(1 H)‐ones and/or phenanthridine‐6(5 H)‐ones were obtained through [3+2] annulation involving aromatic C−H activation or [2+2+2] annulation involving vinylic C−H activation, respectively. Reasonable mechanisms for the formation of these annulation products have been proposed based on density functional theory calculations.

A novel EtO2CCF2-substituted semisquarate is synthesized from diisopropyl squarate by selective 1,2-addition of the Reformatsky reagent derived from BrCF2CO2Et and subsequent rhenium-catalyzed allylic alcohol rearrangement. The compatibility of the highly reactive EtO2CCF2 group in ring transformations of the obtained semisquarate is investigated. Various EtO2CCF2-substituted, highly functionalized compounds, such as quinones, tetronates, cyclopentenones and a bicyclo-[3.2.0]heptenone, are successfully synthesized by ring transformations of the EtO2CCF2-substituted semisquarate. Also, an allylO2CCF2-substituted semisquarate is prepared and converted into the corresponding tetronate. Subsequent palladium-catalyzed deallylation followed by condensation of the resulting carboxylic acid with several amines under mild conditions affords the corresponding α,α-difluoroamides in good yields.