Level 3 – Case 37
250
In Summary
Only by means of primary, secondary and leaving group F KIEs it is not possible
to decide whether the base-promoted HF elimination of ketone 1 follows a concerted or a stepwise mechanism. The double-isotopic fractionation method provides strong evidence for a stepwise process, more likely via an E1cB irr mechanism.
A Ad dd di it ti io on na al l C Co om mm me en nt ts s
This problem is based on the work by Ryberg P, Matsson O (2001) J. Am. Chem.
Soc. 123:2712-2718 and by the same authors in (2002) J. Org. Chem. 67:811-814.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
Elimination reactions. Primary, secondary and heavy atom kinetic isotope effects.
250
In Summary
Only by means of primary, secondary and leaving group F KIEs it is not possible
to decide whether the base-promoted HF elimination of ketone 1 follows a concerted or a stepwise mechanism. The double-isotopic fractionation method provides strong evidence for a stepwise process, more likely via an E1cB irr mechanism.
A Ad dd di it ti io on na al l C Co om mm me en nt ts s
This problem is based on the work by Ryberg P, Matsson O (2001) J. Am. Chem.
Soc. 123:2712-2718 and by the same authors in (2002) J. Org. Chem. 67:811-814.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
Elimination reactions. Primary, secondary and heavy atom kinetic isotope effects.