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When the following cyclopentadiene-fused [14]annulene is
Chapter 18, Problem 18.72(choose chapter or problem)
When the following cyclopentadiene-fused [14]annulene is treated with KH, a green solution of a stable cyclopentadiene anion results. This transformation causes a dramatic change in part of the 1 H NMR spectrum: the methyl groups shift from -3.9 ppm to -1.8 ppm (J. Org. Chem. 2004, 69, 549554). Provide an explanation for this observation. t-Bu t-Bu t-Bu t-Bu KH @
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QUESTION:
When the following cyclopentadiene-fused [14]annulene is treated with KH, a green solution of a stable cyclopentadiene anion results. This transformation causes a dramatic change in part of the 1 H NMR spectrum: the methyl groups shift from -3.9 ppm to -1.8 ppm (J. Org. Chem. 2004, 69, 549554). Provide an explanation for this observation. t-Bu t-Bu t-Bu t-Bu KH @
ANSWER:Step 1 of 2
When Cyclopentadiene-fused [14] annulene is treated with KH, a green solution of a stable cyclopentadiene anion results. This transformation causes a dramatic change in part of the 1 H NMR spectrum, the methyl groups shift from -3.9 ppm to -1.8 ppm. We need to explain the reason for this shift.
Annulenes are monocyclic hydrocarbons that contain conjugated double bonds.