Thermal chemistry of bicyclo[4.2.0]oct-2-enes.

At 300 degrees C, bicyclo[4.2.0]oct-2-ene (1) isomerizes to bicyclo[2.

Thermal reactions of 8-methylbicyclo[4.2.0]oct-2-enes: competitive diradical-mediated [1,3] sigmatropic, stereomutation, and fragmentation processes.

[reaction: see text] At 275 degrees C, 8-exo-methylbicyclo[4.2.0]oct-2-ene (1a) undergoes a [1,3] sigmatropic rearrangement to 5-methylbicyclo[2.