AN EFFICIENT FUNCTIONALIZATION OF [60]FULLERENE - DIELS-ALDER REACTION USING 1,3-BUTADIENES SUBSTITUTED WITH ELECTRON-WITHDRAWING AND ELECTRON-DONATING (SILYLOXY) GROUPS

The Diels-Alder strategy was found suitable for the functionalization of C-60 using 1,3-butadienes substituted with an electron-withdrawing group as well as with an electron-donating group, giving cyclohexene-f used C-60 derivatives having ethoxycarbonyl, acetyl, cyano, phenylsulf onyl and nitro substituents. These cycloadducts were stabilized by con jugation with the substituent and no cycloreversion took place. Though the dienes are electron-deficient in nature, the HOMO (diene) - LUMO (C-60) interaction was significant as indicated by PM3 calculations. ( C) 1996 Elsevier Science Ltd