Selective synthesis of spiro and dispiro compounds using Mn(III)-based oxidation of tetracarbonyl compounds

The Mn(III)-based oxidation of methylenebis(cyclohexanedione)s and methylenebis(piperidinedione)s as a tetracarbonyl compound was investigated under various conditions, selectively producing spiro dihydrofurans and dispiro cyclopropanes depending on the solvent. The mechanism for the formation of the spiro dihydrofurans and dispiro cyclopropanes was discussed. In addition, a simple synthesis of a new type of alkaloid, 3,4,6,7,8,10-hexahydro-1H-pyrano[3,2-c:5,6-c’]dipyridine-1,9(2H)-diones, was demonstrated. [Display omitted] •We developed a very simple synthesis of the spiro dihydrofurans and dispiro cyclopropanes based on the Mn(III)-based oxidation.•The spiro dihydrofurans and dispiro cyclopropanes were selectively produced depending on the protic and aprotic solvents.•The selective production could be interpreted by the Mn(III)-enolate intermediate formation in each protic and aprotic solvent.•We also demonstrated the simple synthesis of new 3,4,6,7,8,10-hexahydro-1H-pyrano[3,2-c:5,6-c’]dipyridine-1,9(2H)-dione alkaloid.