Ring Contraction of 1,2-Digermacyclohexa-1,4-diene to (Germacyclopent-3-enyl)germylene
摘要:
Thermolysis of cis,cis-1,6,7-trigerma-1,6,7-tris(tri-tert-butylsilyl)-7-mesityl-3,4-dimethylbicyclo[4.1.0]-hept-3-ene (1a) and cis,cis-1,6,7-trigerma-1,6-7-tris(tri-tert-butylsilyl)-7-mesityl-3-methylbicyclo[4.1.0]hept-3-ene (1b) at 70 degreesC in benzene in the presence of diphenylacetylene and triethylsilane yielded products arising from (germacyclopent-3-enyl)germylene, which is formed by the ring contraction of 1,2-digermacyclohexa-1,4-diene. Theoretical calculations on this contraction leading from a six-membered ring with a Ge=Ge double bond to a five-membered ring have also been performed.