Oxazaborolidinium Ion Catalysed Asymmetric Diels-Alder Reactions of Anthracene Derivatives

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Many molecules in Nature exist in two different forms which have the same connectivity of atoms and bonds, but differ in their arrangement of atoms and groups in space. These different forms are termed enantiomers and much effort in modern synthetic organic chemistry as been devoted to developing efficient routes that facilitate the selective preparation of one enantiomer over another. One of the more established ways to address this problem is to attach a chiral auxiliary to the substrate of choice, the function of which is to control the selectivity of a given process, followed by subsequent removal and recovery of the auxiliary. We have previously developed efficient methodology that employs an alternative auxiliary approach using an asymmetric Diels-Alder cycloaddition reaction of chiral substituted anthracenes. This methodology has been very successful for a number of alkene substrates and we have developed efficient chemical syntheses of several classes of natural products. This project aims to considerably widen the scope and applicability of this process by developing the first catalytic asymmetric Diels-Alder cycloaddition of anthracene and its derivatives. We aim to conduct a series of optimisations to map the reactivity and selectivity of appropriate anthracene and alkene substrates. Once this has been performed we will conduct asymmetric transformations of the products obtained, in particular looking at Grignard additions and enolate alkylation. The chemistry developed will then be applied to the preparation of two structurally related natural product targets to showcase the efficiency of the overall procedure. In parallel to the work described here, we will also aim to develop alternative catalyst systems based up cis-2-amino-indan-1-ol, a catalyst precursor for which we have considerable experience.