Quantifying Electrophilicity and Nucleophilicity
|Herbert Mayr , Florian Seeliger , Stefan Berger|
LMU München, Department Chemie und Biochemie, Butenandtstrasse 5-13, München 81377, Germany
Reactions of donor stabilized carbocations with electron-rich π-systems and reactions of acceptor substituted carbanions with electron-poor π-systems are often treated as representatives of different classes of reactions - carbocation chemistry on one side, and carbanion chemistry on the other side.
We now demonstrate that the nucleophilicity parameters N and s, as defined by eq. 1 and previously derived from reactions of carbanions with benzhydrylium ions and quinone methides , can also be employed for describing the reactions of carbanions with various other types of Michael acceptors (Figure). In this way, carbocations and electron-deficient ethylenes can be located on a common electrophilicity scale while carbanions and electron-rich ethylenes can be located on a common nucleophilicity scale.
Figure. Plot of (log k)/s for the reactions of carbanions with electrophiles in DMSO at 20 °C versus the nucleophilicity parameters N of the carbanions. a) C6H4X = julolidyl
 H. Mayr, A. R. Ofial, Pure Appl. Chem. 2005, 77, 1807-1821.
 T. B. Phan, M. Breugst, H. Mayr, Angew. Chem. Int. Ed. 2006, 45, 3869-3874.
Presentation: oral at 18th Conference on Physical Organic Chemistry, Symposium 1, by Herbert Mayr
See On-line Journal of 18th Conference on Physical Organic Chemistry
Submitted: 2006-05-31 17:38 Revised: 2009-06-07 00:44
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