- 47 views
- 31 downloads
Computations Reveal That Electron-Withdrawing Leaving Groups Facilitate Intramolecular Conjugate Displacement Reactions by Negative Hyperconjugation.
-
Intramolecular conjugate displacements are stepwise: Computational evaluations of the mechanism
-
- Author(s) / Creator(s)
-
Intramolecular conjugate displacement (ICD) reactions, developed by the Clive
group, form carbocycles and cyclic amines by intramolecular nucleophilic attack on a
Michael acceptor with an allylic leaving group. Quantum mechanical investigations with
density functional theory show that ICDs involve a stepwise addition, forming an
intermediate stabilized carbanion, followed by elimination. The electron-withdrawing
nature of the allylic leaving group facilitates the addition by negative hyperconjugation;
the twist-boat conformation of the addition and intermediate is stabilized by this
interaction. In the absence of an activating electron-withdrawing group as part of the
Michael acceptor a high-energy concerted SN2` reaction occurs. The reactions of carbon
nucleophiles have lower activation energies than those of amines. -
- Date created
- 2016-01-01
-
- Type of Item
- Article (Draft / Submitted)