Investigation of the products of the addition of mercury salts to disubstituted acetylenes

Summary

• 1. On the basis of a study of their infrared absorption spectra, thea-isomer of 2-acetoxy-1-methylpropenyl-mercury chloride, which has a C=C frequency at 1667 cm⁻¹, is assigned the trans configuration, and its stereoisomer, which has a C=C frequency of 1655 cm⁻¹, is assigned the cis configuration.

• 2. Bis(2-acetoxy-1-methylpropenyl)mercury of m.p. 114, which has a C=C frequency of 1621 cm⁻¹, has been assigned to the trans series, and its stereoisomer of m.p. 101, which is obtained from theβ-compound and has a C=C frequency of 1616 cm⁻¹, has been assigned the cis-cis configuration.

• 3. Two new stereoisomeric bis(2-acetoxy-1-methylpropenyl)thallium chloride have been synthesized from the stereoisomeric bis(2-acetoxy-1-methylpropenyl)mercurys and thallium trichloride, and some of their chemical properties have been investigated. Their geometric configurations have been established by the method of even and odd cycles.

• 4. It has been shown that the stereoisomeric bis(2-acetoxy-1-methylpropenyl)mercurys react at different rates with thallium trichloride, the trans-trans compound reacting much more rapidly that the cis-cis isomer.

• 5. A new reaction has been described in which organothallium compounds of the type RTICl₂ are synthezised directly from symmetrical organomercury compounds and thallium trichloride.

• 6. By means of a symmetrization reaction, bis(2-acetoxy-1-methylallyl)mercury has been prepared, and some of its chemical properties have been studied. It reacts with thallium trichloride with formation of bis(2-acetoxy-1-methylallyl)thallium chloride.

• 7. It has been shown that in the symmetrization and reverse dissymmetrization reactiions and also in the double-decomposition reactions with metal salts, the transfer of the 2-acetoxy-1-methylpropenyl group

  

  from one metal atom to another and back occur without any change in geometric configuration. This behaviour confirms the rule that we have established relating to the preservation of the configuration ogf cis and trans isomers in metathetic reactions with electrophilic reagents and in homolytic exchange reactions.