Sub-5 fs pulse dynamics observed in neat chloroform (CHCl3) and the CHCl3 ⋯ O2 charge-transfer complex in oxygen-saturated chloroform (O2-CHCl3) were found to be dominated by wave packet motions in the excited state and the ground state, respectively. The time-resolved signal of CHCl3 exhibits dynamics in the electronic excited state generated by a three-photon absorption process, and that of O2-CHCl3 is explained in terms of the dynamics of the electronic ground state excited by the stimulated Raman process. In addition, we found that the oxidation reaction of chloroform in the charge-transfer complex of chloroform and oxygen easily proceeds via a C-H insertion process triggered by the stimulated Raman process under the irradiation of a visible laser pulse. The spectrogram analysis enabled direct observation of the realtime dynamics of the Raman-triggered oxidation process. These results demonstrate that observation of transition states by sub-5 fs time-resolved spectroscopy is applicable to "ground-state reactions" as well as "excited-state reactions" via stimulated Raman excitation in a wide variety of chemical reactions.