In the presence of Pd(PPh3)4 (2.5 mol%), PPh3 (10 mol%) and pyridine (2.0 equiv.), the formal [5+3] cycloaddition of vinylethylene carbonates with isatin‐based α‐(trifluoromethyl)imines proceeded readily, and delivered trans‐configured novelmedium‐heterocycle‐fused spirooxindoles in 75–97% chemical yields with excellent diastereoselectivities. The relative stereochemical configuration of the title products was identified by X‐ray diffraction analysis.magnified image

Catalyzed by Pd 2 (dba) 3 . CHCl 3 and PPh 3 , the formal [4 + 2] cycloaddition between vinyl benzoxazinones and oxazol-5-(4H)-ones proceeded readily and delivered 3,4-disubstituted dihydro-2 (1H)-quinolinones in the reasonable chemical yields with excellent diastereoselectivities. The relative stereochemical configuration of the title products was unambiguously characterized with the use of Xray diffraction analysis.

The formal [5+2] cycloaddition of vinyloxiranes with oxazol‐5‐(4H)‐ones proceeds readily at room temperature in THF in the presence of Pd2(dba)3·CHCl3, dppp, and K2CO3, thus furnishing the desired seven‐membered lactones in 67–96 % yield. The chemical structure of the title compounds was confirmed by X‐ray diffraction analysis.