Cycloaddition reactions of hydrofullerenes with cyano-substituted alkenes under basic conditions
Abstract
Hydrogenated [60]fullerenes, prepared from [60]fullerene and CCN(CO2Et): R = C6H5
(2a), 4-CH3O–C6H4
(2b), 4-NO2–C6H4
(2c), H (2d)] and alkylidenemalononitriles [RCH
C(CN)2: R = C6H5
(2e), 4-CH3O–C6H4
(2f), 4-NO2–C6H4
(2g), 4-(CH3)2N–C6H4
(2h)] under basic conditions to afford cyclopentenylfullerenes 3. No multi-cycloaddition products are obtained. Several bases including organic and inorganic bases can be utilized in these reactions. It is proposed that the reactions take place via the Michael addition of C60H−, generated in situ by deprotonation of dihydrofullerene with a mild base, to the electrophilic carbon-carbon double bond of substrate 2, followed by intramolecular