The project was targeted at the rational design and synthesis of novel and effective chiral reagents for asymmetric synthesis. Emphasis was placed on developing new asymmetric aldol methodology based on chiral boron enolates by transition state modelling using ab initio MO and MM2 calculations. Conformational analysis of the possible diastereomeric transition states was used to assess the sense and degree of stereoselectivity for a wide range of aldol reaction types. The most promising chiral reagents to come from the modelling work were then prepared and their general effectiveness tested experimentally.
Several new reagents have been developed using the 'rational design/molecular modelling' approach. These new reagents allow the synthesis of complex molecules containing multiple stereocentres and are, in principle, exploitable by pharmaceutical companies and/or by the fine chemical industry. The synthesis and application of these reagents have been published in the scientific literature.
A force field was developed to model the transition structures of the boron mediated aldol reaction. The force field has been published in scientific journals. The parameters were included in the distributed version of the commercial package MacroModel (W C Still, Columbia University, New York) in order to make it available to the scientific community.
The proposed project is for the rational design and synthesis of novel and effective chiral reagents for asymmetric synthesis. This work will be based on using ab initio MO and MM2 calculations for modelling the transition states for various addition reactions at sp2 carbon atoms. Emphasis will initially be placed on developing new and general asymmetric aldol methodology based on boron and titanium enolates. Conformational analysis of the possible diastereomeric transition states, when chiral substituents are involved, will be used to assess the sense and degree of reaction stereoslectivity. The most promising chiral reagents to come from the modelling work would be prepared and their general effectiveness tested.
Funding SchemeCSC - Cost-sharing contracts