powerpoint presentation - small ring... · displayed from different angles (but would become...
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Interpretation:
(1) Structures 1-6 are identical, but
displayed from different angles (but
would become different if there
were any substituents).
(2) Primed and unprimed structures
are related by a ring flip (e.g.,
1 and 1’).
(3) Interconversion is possible without
passing through a boat TS!
(4) The boat is destabilized because
of a van der Waals interaction
between the carbons rather than
the “flagpole” protons.
(5) There are substantial deviations
in the boat from tetrahedral angles;
thus, the hybridizations are
not sp3.
diagram: see ref on previous page
Sauers J Chem Ed 2000 77 332
Two Possible Pathways:
(A) chair, half-twist TS, twist intermediate, half twist TS’, chair’
(B) chair, half-twist TS, twist intermediate, boat TS, twist intermediate’,
half-twist TS’, chair’
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