Formation of iminium ions from the condensation of chiral secondary or primary amines with a,b-unsaturated aldehydes or ketones
can be used as an effective platform for the acceleration of a wide variety of catalytic asymmetric cycloaddition and conjugate
addition reactions. The reversible formation of the active iminium ion species simulates the π-electronics and equilibrium
dynamics traditionally associated with Lewis acid activation of a,b-unsaturated carbonyl compounds lowering the energy level
of the LUMO associated with the π-system and activating subsequent reaction. Importantly, these iminium ion catalysed processes
offer the opportunity to conduct reactions in the presence of both moisture and air greatly adding to the practicality and
general applicability of the chemistry described. Proposed catalytic cycles and transition state models for the induction
of asymmetry provide reliable and robust predictive tools for the outcome of reactions and high functional group tolerance
suggests this class of transformation will have broad application in the arena of synthetic organic chemistry as the area
matures. This review describes the rapid expansion of iminium ion catalysis over recent years from its conceptual introduction
to the development of a whole new arsenal of highly practical and effective methods with which to approach challenging and
fundamental bond construction processes.
can be used as an effective platform for the acceleration of a wide variety of catalytic asymmetric cycloaddition and conjugate
addition reactions. The reversible formation of the active iminium ion species simulates the π-electronics and equilibrium
dynamics traditionally associated with Lewis acid activation of a,b-unsaturated carbonyl compounds lowering the energy level
of the LUMO associated with the π-system and activating subsequent reaction. Importantly, these iminium ion catalysed processes
offer the opportunity to conduct reactions in the presence of both moisture and air greatly adding to the practicality and
general applicability of the chemistry described. Proposed catalytic cycles and transition state models for the induction
of asymmetry provide reliable and robust predictive tools for the outcome of reactions and high functional group tolerance
suggests this class of transformation will have broad application in the arena of synthetic organic chemistry as the area
matures. This review describes the rapid expansion of iminium ion catalysis over recent years from its conceptual introduction
to the development of a whole new arsenal of highly practical and effective methods with which to approach challenging and
fundamental bond construction processes.
- Content Type Book Chapter
- DOI 10.1007/128_2008_28
- Authors
- John B. Brazier, Cardiff University School of Chemistry, Main Building Park Place Cardiff CF10 3AT UK
- Nicholas C. O. Tomkinson, Cardiff University School of Chemistry, Main Building Park Place Cardiff CF10 3AT UK
- Book Series Topics in Current Chemistry
- Online ISSN 1436-5049
- Print ISSN 0340-1022
- Book Series Volume Volume 291/2009
- Book Asymmetric Organocatalysis
- DOI 10.1007/978-3-642-02815-1
- Print ISBN
Nano Letters, Volume 10, Issue 5, Page 1537-1541, May 12, 2010. [...]