Electron transfer from toluene anions to CO2, 1,3-butadiene, and pyrimidine was studied at high pressure (1-3 kbar). For these solutes the second-order rate constants for transfer are in the range (0.2-3.0) x 10(12) m(-1) s(-1). This high reactivity is associated with the high mobility of toluene anions. Electron transfer to butadiene is reversible, and Delta G(r)(298) is -10.0 kcal/mol in toluene. This reaction shifts to the left with increasing temperature and to the right on dilution of the toluene with n-pentane. The pressure dependence is slight; the volume change is -0.7 +/- 0.6 cm(3)/mol.