Sigmatropic Rearrangements Flashcards
1
Q
Claisen rearrangement
A
Vinyl allyl ether/aryl allyl ether rearranges to γ,δ-unsaturated carbonyl compound
2
Q
Cope rearrangement
A
All-carbon version of Claisen rearrangement
3
Q
[3,3] Sigmatropic rearrangements
A
Usually reversible unless there’s a driving force that pushes equilibrium to one side
4
Q
[1,n]-shifts
A
Can occur suprafacial or antarafacial (only if sterically possible)
5
Q
Carbocations and H-shifts
A
Susceptible to [1,2]-H shifts to form more stable carbocation, must occur suprafacially
6
Q
[1,3]-C shifts allowed?
A
Thermally allowed, C can undergo suprafacial migration where back lobe of sp3 orbital has right phase to overlap with orbital on carbon to which the carbon migrates, overall inversion of stereochemistry
7
Q
Ene reaction
A
2 alkenes and allylic H
