Silicon-carbon unsaturated compounds. 65. Thermal and photochemical isomerization of trimethylsiloxy- and bis(trimethylsilyl)-substituted silacyclobut-3-enes

摘要

Heating silacyclobut-3-ene 2 at 250 degreesC afforded the trans-silacyclobut-3-ene 4, via the silyl-substituted cycloprop-2-ene 3. The photolysis of 4 gave a 1:1 mixture of 4 and the cis isomer 6, which was transformed into 4 at 250 degreesC, quantitatively. Preliminary results of the theoretical treatment for the isomerization of 2degrees to 3degrees are described. [References: 22]