Direct Synthesis of Organotrichlorogermanes by the Reaction of Elemental Germanium, Hydrogen Chloride, and Alkene

Abstract

The reaction of elemental germanium, hydrogen chloride, and ethylene with copper(I) chloride catalyst gave ethyltrichlorogermane with a 66% selectivity, tetrachlorogermane also being formed. The addition of tetrachlorogermane to the reaction system increased the formation rate of ethyltrichlorogermane. The reaction of germanium, tetrachlorogermane, and butadiene resulted in the formation of 1,1-dichlorogermacyclopent-3-ene. These results indicate the intermediacy of dichlorogermylene, which is formed by the reaction of elemental germanium with tetrachlorogermane. In place of ethylene, allyl chloride was fed with hydrogen chloride. Allyltrichlorogermane was obtained with a 92% selectivity together with a small amount of tetrachlorogermane. It is highly plausible that the formation of allyltrichlorogermane is caused by the insertion of dichlorogermylene intermediate to the carbon-chlorine bond of allyl chloride.

Organotrichlorogermane synthesis by the reaction of elemental germanium, tetrachlorogermane and organic chloride via dichlorogermylene intermediate

“…In our previous paper, 10 the formation of dichlorogermylene by the reaction of elemental germanium with tetrachlorogermane was reported. The reaction of germanium, tetrachlorogermane and butadiene gave 1,1-dichlorogermacyclopent-3-ene, which is an inherent product formed by the reaction of germylene with butadiene (eqn.…”

“…PrCl → C 3 H 6 + HCl (6) Hydrogen chloride can easily react with elemental germanium to form tetrachlorogermane probably via a dichlorogermylene intermediate 10 as shown in eqn. ( 7).…”

“…We have found that the reaction of elemental germanium, hydrogen chloride and alkene gave alkyltrichlorogermane and that dichlorogermylene is added to the double bond of alkene to form the germacyclopropane intermediate reacting with hydrogen chloride to give alkyltrichlorogermane. 10 The reaction of elemental germanium, hydrogen chloride (5 mmol h −1 ) and propylene (10 mmol h −1 ) at 400 °C gave 0.36 mmol of propyltrichlorogermane selectively together with 0.02 mmol of isopropyltrichlorogermane. The reaction pathway for the formation of propyltrichlorogermanes is shown in eqn.…”

“…The elemental germanium charged was completely consumed at 6 h. The effluent rate of tetrachlorogermane was almost the same as the feed rate of tetrachlorogermane, indicating that tetrachlorogermane is formed; therefore, allyl chloride is decomposed to give hydrogen chloride and propadiene/propyne (eqn. (10)).…”

“…4 Many stable germylenes 5 and germylene complexes 6 have been reported and used for the synthesis of various organogermanium compounds. Dichlorogermylene is one of simple germylenes, and can be prepared by the some methods; 7 for instance, the reaction of elemental germanium and tetrachlorogermane, [8][9][10] and the reaction of tetrachlorogermane with dichlorosilylene obtained by the pyrolysis of hexachlorodisilane 11 or 1,1-dichlorosilacyclopent-3ene. 12 Among the methods for formation of the germylene, the first example is very simple and practical, since elemental germanium and tetrachlorogermane are easily available and stoichiometric amounts of byproducts are not formed.…”