The treatment of indoles with trimethylhalogenosilanes and sulphoxides J. Chem. Res. (S) 1989, 182

Indole derivs. I (R = H, Me; R1 = H, Me, Ph; R2 = H) were treated with DMSO and Me3SiCl to give I (same R, R1; R2 = S+Me2 Cl-). Treatment of I with Me3SiCl and Et2S(O) gave mainly I (same R, R1; R2 = Cl). No sulfonium compds. were formed when I (R = R2 = H; R1 = H, Me) were treated with Me3SiCl and Bu2S(O) or with Me3SiBr and DMSO. Treatment of I (R = H, R1 = R2 = Me) with Me3SiCl and DMSO gave 56% I (R = H, R1 = Me, R2 = CHO). The formation of different electrophilic S or Cl species is given as an explanation for product formation.