2012 Volume 70 Issue 12 Pages 1242-1254
To surpass enzymes, the potential of supramolecular catalysts to realize anomalous stereoselectivity in organic synthesis is highly attractive. However, to date, there have been a few examples of non-polymeric and non-covalent chiral supramolecular catalysts that induce both practical yield and excellent stereoselectivity. To establish high catalytic activity with anomalous stereoselectivity, in principle, an artificial cage should be conformationally flexible, like an active pocket in an enzyme with an induced-fit function. In this article, we focus on the anomalous endo/exo-selective enantioselective Diels-Alder reaction, and show the development of the successive catalysts including our recent highly active, conformationally flexible, and chiral supramolecular catalysts. The evolution from ‘ready-made’ single-molecule catalysts to ‘tailor-made’ supramolecular catalysts could offer not only high enantioselectivity but also high anomalous endo/exo-selectivity due to substrate-specific characteristics, as with enzymes.
