Allyl rearrangement in triallylboron

Structurally Defined Allyl Compounds of Main Group Metals: Coordination and Reactivity

“…Gas‐phase electron diffraction experiments in combination with quantum‐chemical calculations revealed the expected η 1 coordination mode of the allyl ligand and a slight pyramidalization of the boron atom 79. In the liquid phase, the allyl ligands are bonded at the metal center in an η 1 fashion, as evident from NMR spectroscopic analysis at −40 °C, but show fluxional behavior at higher temperatures 80. Activation parameters of the exchange process have been determined (Δ G ≠,298 =(61.65±3.08) kcal mol −1 ) 81.…”

“…In addition, activation parameters of the allyl‐exchange reactions have been determined by means of variable‐temperature (VT) NMR spectroscopic measurements in combination with line‐shape analysis. Low values for the activation entropy Δ S ≠ indicate an ordered transition state, but the interpretation in terms of the molecularity of the allyl exchange is controversial 80–82. 109 A third mechanism accounting for allyl exchange is the thermally induced suprafacial [1,3]‐sigmatropic rearrangement (Scheme ).…”

Allyl‐Aluminium Compounds

“…This behaviour is completely analogous to that of iris-allyl-boron [4], which was interpreted by assuming the existence of a normal allylic structure at low temperature and a dynamic structure involving rapid exchange with allylic rearrangement a t higher temperatures.…”

Allylboranes and the synthesis of diamond molecules

“…13 Investigations of the permanent allylic rearrangement for a large num ber of allylic organoboranes revealed the influence of certain structural and electronic factors on the reaction rate 14-24 ( Table 2).…”