The 2008 Benjamin Franklin Medal in Chemistry is presented to Albert Eschenmoser, Dr. sc.nat

The Franklin Institute, Philadelphia, Pennsylvania, awards the 2008 Benjamin Franklin Medal in Chemistry to Professor Albert Eschenmoser for his seminal efforts in the chemical etiology of nucleic acid structure, which through systematic exploration employing chemical synthesis of potentially natural structural alternatives to DNA, demonstrated that Watson-Crick base pairing is not unique to the ribofuranosyl system, and that DNA's structure represents an optimization of several factors rather than a maximization of base-pairing strength.In his early scientific career, Professor Albert Eschenmoser established himself as one of the premier synthetic organic chemists in the world, with the monumental achievement of two total syntheses of Vitamin B12, the first in collaboration with Professor Robert B. Woodward of Harvard University.However, since the 1980s, Professor Eschenmoser has concentrated his research interest in establishing the area of chemical etiology of nucleic acid structures to understand better the structural and functional uniqueness of the molecular basis of nature's genetic information carrier-DNA and RNA. This systematic investigation of potential natural nucleic acid alternatives has demonstrated experimentally that Watson-Crick base pairing is not a unique property of DNA and RNA. Moreover, his research on homo-DNA revealed that the helicality of the famous double-stranded DNA is a direct outcome of the 5-membered ring nature of the deoxyribofuranose structure unit, while the study on p-RNA demonstrated that nature did not choose her genetic system by the standard of maximal base pairing strength, but instead optimization. Of equal significance, his recent design and synthesis of TNA (α-threofuranosyl nucleic acid), found to possess extraordinary base-paring properties, led to the hypothesis suggesting TNA as a possible precursor to the “RNA World”. Finally, his research on the correlation between the differences in the pKa of nucleic bases and their base-pairing strength led to a novel principal for the selection of nucleic base alternatives with proper bonding strength.