Chemoselective syntheses of spirodihydrofuryl and spirocyclopropyl barbiturates via cascade reactions of barbiturate-based olefins and acetylacetoneElectronic supplementary information (ESI) available. CCDC 1888031. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c9ob00004f

The Michael addition initiated ring closure reaction of barbiturate-based olefins and acetylacetone with NBS has been explored. The efficient and chemoselective approach for the synthesis of barbiturate-fused spirocycles was established. Spirodihydrofuryl barbiturates and spirocyclopropyl barbiturates were synthesized selectively via cascade reactions under different basic conditions in moderate to excellent yields. The structure of 2-(4-chlorophenyl)-1,1-diacetyl-5,7-dimethyl-5,7-diazaspiro[2,5]octane-4,6,8-trione was confirmed by single crystal X-ray diffraction analysis. Spirodihydrofuryl and spirocyclopropyl barbiturates were chemoselectively synthesized from barbiturate-based olefins and acetylacetone in the presence of different bases and NBS.