STUDIES IN SILICO-ORGANIC COMPOUNDS. X. THE CHEMICAL PROPERTIES OF TRISUBSTITUTED SILANES^1,2

Abstract

1. By direct halogenation in carbon tetrachloride, the following have been prepared: triethylchlorosilane, tribenzylchlorosilane, triethylbromosilane, tricyclohexylbromosilane, and tribenzylbromosilane.2. Benzoyl chloride has been found to react with tribenzylsilane to form benzaldehyde and tribenzylchlorosilane. With triethylsilane a comparable reaction

B(C6F5)3 catalysis accelerates the hydrosilane chlorination by Ph3CCl

“…A chlorination of hydrosilanes using several strong chlorinating reagents in a stoichiometric ratio was successfully applied. Forcing conditions using gaseous chlorine were published for the chlorination of tertiary silanes R 3 SiH (R = Et, Bn) in CCl 4 as a solvent with moderate yields (<60%) . A milder yet quantitative chlorination of tertiary silanes R 3 SiH (R = Ph, Et) was published by Corey …”

“…The adduct formation enhances the polarization of the Si‐H bond and facilitates the nucleophilic attack of chloride on the electropositive silicone center. For historical reasons AlCl 3 was used as the first LA catalyst for the chlorination, while neopentyl‐, hexyl‐, and benzoyl‐ chlorides were applied as chloride sources, yet with low to moderate yields . More efficient catalyst, CuI in combination with CuCl 2 as a chloride source, leading to high yields (typically 60–80%) of chlorosilanes, was introduced by Ishikawa .…”

“…Forcing conditions using gaseous chlorine were published for the chlorination of tertiary silanes R 3 SiH (R = Et, Bn) in CCl 4 as a solvent with moderate yields (<60%). [2] A milder yet quantitative chlorination of tertiary silanes R 3 SiH (R = Ph, Et) was published by Corey. [3] However, using a strong Lewis acid (LA) as a catalyst for chloride transfer from the respective chlorinating reagent to the silicon atom was much more common.…”

“…For historical reasons AlCl 3 was used as the first LA catalyst for the chlorination, while neopentyl-, hexyl-, and benzoylchlorides were applied as chloride sources, yet with low to moderate yields. [2,4] More efficient catalyst, CuI in combination with CuCl 2 as a chloride source, leading to high yields (typically 60-80%) of chlorosilanes, was introduced by Ishikawa. [5] This methodology allows also selective monochlorination of secondary hydrosilanes, however, it suffers from the necessity of 2-fold excess of CuCl 2 to transfer a single chloride functionality.…”

The Selective Monohalogenation of Dihydro- and Trihydrosilanes

“…Perhaps this is because chlorine is too reactive in the absence of bulky substituents. Literature reports (6) indicate that the order of reactivity for halogenation of hydrosilanes is Cl 2 ú Br 2 ú I 2 . Therefore, the slower halides were studied in the hopes that one of them might be more selective than chlorine.…”