Synthesis and dynamic behaviour of 1-(dipropylboryl)cyclohepta-2,4-diene

Two sequential [1,3] boron shifts in 1-(dipropylboryl)cyclohepta-2,4-diene 1 result in a degenerate rearrangement (E_A=98.9±3.3.kJ mol⁻¹, ln A=39.3±1.4, ΔG298≠ =118.3±0.3 kJ mol⁻¹); reaction of 1 with acetone affords non-conjugated alcohol 2.