Organocatalysts - small enzyme mimics: The development of small metal-free molecules capable of catalysing reactions while transferring stereochemical information from catalyst to product (organocatalysis) is a very much a ‘hot-topic’ at the moment - undoubtedly it is one of the fastest moving and rewarding fields in contemporary organic chemistry.
Our group is pursuing the synthesis and evaluation of novel bifunctional catalysts that mimic an important facet of enzymatic action – the ability to act as both a Lewis-acid and a Lewis-base simultaneously. This allows the catalyst to potentially activate both the electrophilic and nucleophilic reaction components simultaneously.
These catalysts are potentially very useful molecules of broad scope, with applications in cycloaddition processes and nucleophilic addition chemistry. A particular focus for this work is the catalysis of the notoriously slow Baylis-Hillman reaction between aldehydes and Michael acceptors, which furnishes densely functionalised products of high synthetic utility together with the formation of a new stereocentre.
We aim to design and prepare conceptually novel chiral catalysts incorporating both Lewis-basic (nucleophilic) and Lewis-acidic (H-bonding) groups capable of both accelerating this fascinating and synthetically useful reaction and generating the products with high levels of enantiomeric excess.
Would suit an enthusiastic student with an interest in organic synthesis and catalysis keen on joining a vibrant group of ca. 12 researchers. The student will have the opportunity to develop their skills in (training will be provided) the following core areas: organic synthesis, NMR spectroscopy, analytical HPLC, catalysis.
Students interested in undertaking a PhD in the our group in this research area should register their interest as soon as possible. Informal enquiries can be made to Dr Stephen Connon (connons@tcd.ie).
Funding Notes
Fully funded (including fees). Candidates must be a citizen of the European Union.
Keen interest in organic chemistry is essential.
Recent representative publications from our group (* indicates bifunctional catalysis work)
S. A. Kavanagh, A. Piccinini, E. M. Fleming and S. J. Connon
Urea derivatives are highly active catalysts for the base-mediated generation of terminal epoxides from aldehydes and trimethylsulfonium iodide
Org. Biomol. Chem. 2008, 6, 1339
A. Peschiulli, Y. Gun’ko and S. J. Connon*
Highly enantioselective desymmetrization of meso anhydrides by a bifunctional thiourea- based organocatalyst at low catalyst loadings and room temperature
J. Org. Chem. 2008, 73, 2454
E. M. Fleming, C. Quigley, I. Rozas* and S. J. Connon
Computational study-led organocatalyst design: A novel, highly active urea-based catalyst for addition reactions to epoxides
J. Org. Chem. 2008, 73, 948
C. O Dálaigh and S. J. Connon*
Non-acylative kinetic resolution of Baylis-Hillman adducts
J. Org. Chem. 2007, 72, 7066.
C. O Dálaigh, S. A. Corr, Y. Gun’ko and S. J. Connon
A magnetic nanoparticle-supported 4-N,N-dialkylaminopyridine catalyst: Excellent reactivity combined with facile catalyst recovery and recyclability
Angew. Chem. Int. Ed. 2007, 46, 4329.
B. Procuranti and S. J. Connon*
A reductase-mimicking thiourea organocatalyst incorporating a covalently bound NADH analogue: efficient 1,2-diketone reduction with in situ prosthetic group generation and recycling
Chem. Commun. 2007, 1421.
S. H. McCooey and S. J. Connon*
Readily accessible 9-epi-amino cinchona alkaloid derivatives promote efficient, highly enantioselective additions of aldehydes and ketones to nitroolefins
Org. Lett. 2007, 9, 599.
S. H. McCooey, T. McCabe, and S. J. Connon*
Stereoselective synthesis of highly functionalized nitrocyclopropanes via organocatalytic conjugate addition to nitroalkenes
J. Org. Chem. 2006, 71, 7494.
S. H. McCooey and S. J. Connon*
Novel urea-substituted cinchona alkaloid derivatives as highly active and selective asymmetric bifunctional organocatalysts: inversion of configuration at C-9 dramatically improves catalyst performance
Angew. Chem. Int. Ed. 2005, 44, 6367
J. E. Murtagh, S. H. McCooey and S. J. Connon
Novel amine-catalysed hydroalkoxylation reactions of alkenes and alkynes
Chem. Commun. 2005, 227
C. Faltin, E. M. Fleming and S. J. Connon*
Acrylamide in the Baylis-Hillman reaction: expanded reaction scope and the unexpected superiority of DABCO over more basic tertiary amine catalysts
J. Org. Chem. 2004, 69, 6496
D. J. Maher and S. J. Connon*
Acceleration of the DABCO-promoted Baylis–Hillman reaction using a recoverable H-bonding organocatalyst
Tetrahedron Lett. 2004, 45, 1301.
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