摘要:
The fluxional behavior of the E (4a) and Z (4b) isomers of 2,4-pentadienyldipropylborane has been studied by dynamic H-1 and C-13 NMR spectroscopy. Activation barriers have been determined for degenerate metallotropic rearrangements of 4a and 4b and for 4a reversible 4b interconversion by complete line shape analysis of C-13 DNMR spectra. The data obtained suggest, that only 1,3 shifts of BPr2 groups take place in both isomers rather than 1,5 sigmatropic shifts.