Organosilicon compounds were directly synthesized from metallic silicon, alkene/alkyne and HCl, EtHSiCl₂ being obtained with 47% selectivity from Si, C₂H₄ and HCl at 513 K, and CH₂CHSiHCl₂ and EtHSiCl₂ with 39 and 23% selectivity, respectively, when C₂H₂ was used in place of C₂H₄.