REACTION OF 2-LITHIO-3.4-BIS(TRIFLUOROMETHYL)FURAN WITH ELECTROPHILES

2-Substituted-3,4-bis(trifluoromethyl)furans activated CH = C(CF3)C(CF3) = CR-O [R = CO2H (and hence R = CO2Me and CO2Et), CHO, CHPhOH, CHMeOH, CH(OH)CH = CH2] are obtained in good yield by treatment of the corresponding 2-lithiofuran with the appropriate electrophile. With methyl acrylate, initial attack occurs at carbonyl carbon but the resulting ketone (R = COCH = CH2) undergoes Michael addition with an excess of the lithium salt. From the reaction with dichloromaleic anhydride, 5,5-bis[3,4-bis(trifluoromethyl)-2-furyl]-3,4-dichloro-2-furanone is formed in 85% yield.