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Despite major advances in organic synthesis predominantly over the past hundred years or so, asymmetric synthesis of chiral organic compounds including the great majority of bioactive compounds , such as amino acids and their oligomers and polymers , i.e. , peptides , has remained as one of the "last bastions" to be conquered .
As alarmed by the unfortunate incident of a tranquilizer, Thalidomide,1 any bioactive organic compounds of biological and medicinal concerns must be prepared in the "YESES " manners, satisfying all of the following requirements including (i) high Y ields, (ii) high E fficiency to be reflected most significantly in the number of synthetic steps, (iii) high S electivity leading to high purity as high as required, (iv) E conomy mandating highly catalytic processes, and (v) last but not least, unfailing S afety, which is often closely linked with S electivity.
As is well known, discovery of the existence of enantiomeric isomers of organic compounds as well as their isolation as enantiomerically pure isomers with the use of tweezers under microscope were performed for the preparation of enantiomerically pure D-(-)- and L-(+)-tartaric acids as early as the mid-nineteenth century by L. Pasteur.2,3
Approximately half a century later, the first Nobel Prize in Chemistry was awarded to J. H. van't Hoff in 1901.4 Among his various contributions pertaining to the relationships between configurations of C atoms and various physical and chemical properties including chirality, optical activity, and so on, he predicted that α,ω-di-, tri-, or tetrasubstituted cumulenes, i.e. , [Image Omitted: See PDF], can be chiral and optically active in cases where the number of cumulating C=C, i.e. n , is odd and 3 or higher.5,6
The second Nobel Prize in Chemistry in 1902 recognized E. Fischer's astounding achievements in the syntheses of various complex organic compounds including a number of mono- and oligosaccharides.7,8 As monumental as his diastereoselective syntheses were, additionally and more critically needed were enantioselective syntheses of a wide range of chiral organic compounds, as complementary, supplementary, and hopefully superior routes to the desired chiral organic compounds. This, however, proved to be a highly challenging goal.
Historically, yet another fundamentally significant advance in the asymmetric synthesis of chiral organic...