Exceptionally strong, neutral, enantiomerically-pure diamine bases

Lead Research Organisation: University of Bristol
Department Name: Chemistry

Abstract

Chemists describe molecules that accept or remove a proton from another molecule as a 'base', and the compound that donates the proton as a 'Bronsted acid'. The removal and addition of protons is ubiquitous in organic and biological chemistry and is an essential part of many synthetic manipulations by which chemists can contruct new or known molecules in a logical and efficient manner. Deprotonation (removal of a proton by a base) of a neutral organic molecule generates a negatively charged product, described as an 'anion', Deprotonation at a carbon atom in an organic molecule generates a 'carbanion' and this is often conducted as part of a synthetic procedure so as to provide the requisite reactivity towards other another species, and thus allow the formation of new molecules. Many organic molecules are chiral ('handed') and thus exist in two mirror image forms. For approval, license and prescription, pharmaceuticals (>99 % of which are organic molecules) that are chiral must usually be prepared as a single mirror image form. In the absence of any form of control, chemical reactions afford an equal mixture of mirror images. One method thus involves separating the mixture into its two components, know as resolution. Another method involves using carefully designed or optimsed chemical control systems which are themselves chiral and that influence the path so as to bias it heavily towards one mirror image or the other. Such a technique is known as asymmetric synthesis and new methods to exert such control are always needed. This proposal describes the design of a new class of bases that we propose will be able to selectively deprotonate organic molecules so as to generate unequal mixtures of mirror image products, ideally in ratios > 99 / 1, thereby providing the synthetic chemist with a new asymmetric synthesis tool for control of reactions. The major part of the work proposed will, ironically, be involved in preparing the new bases as single mirror image forms, using selective metal catalysts developed by others in the field of asymmetric synthesis. Of course, the workers who developed these catalysts had no intention that they would be used to prepare such bases and this point demonstrates the importance of new asymmetric methods - the benefits can be wide and in some ways unpredictable. We are confident in the design of our novel chiral base systems and aspire to provide the community with a reagent that will be available in large quantity, be highly efficient, and thus widely applied.

Publications

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Evans L (2009) 16 th European Symposium on Organic Chemistry (ESOC 16), Prague, Czech Republic in European Journal of Organic Chemistry

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Lloyd-Jones G (2011) A Metathesis Approach to Volatile Olefins: Synthesis of 18O-Allyl Alcohol in Chemistry - A European Journal

 
Description Routes to strong bases involving amines
Exploitation Route Metathesis methodologies for volatile alkene synthesis
Sectors Chemicals