The 1,5-sigmatropy of 3,3-diphenyl-3,3a-dihydrocyclohepta[b]furan-2-one was examined in dibutyl ether to 1600 bar at 130 °C. The rearrangement was slightly accelerated with pressure, and was different to the pressure effect of 1,5-sigmatropy of cyclopentadienes. The activation volume was in the range of the concerted process, but its transition state was as loose as those biradical-like.
3,3
-二苯基-3,3a-二氢
环庚烷[b]
呋喃-2-酮的 1,5-σ 向性在
二丁醚中于 130 °C 下检测到 1600 bar。重排在压力下略有加速,与
环戊二烯的1,5-sigmatropy的压力效应不同。活化体积在协同过程范围内,但其过渡态与双自由基一样松散。