Perspectives in Chemistry and Chemical Biology' a Symposium Celebrating Prof

CONFERENCE REPORT 364

CHIMIA 2000, 54, No, 6

CONFERENCE REPORT

Chimia 54 (2000) 364-366 © Neue Schweizerische Chemische Gesellschaft ISSN 0009-4293

'Perspectives in Chemistry and Chemical Biology' A Symposium Celebrating Prof. A. Eschenmoser's Contributions to Chemistry on the Occasion of the Spring Meeting 2000 of the New Swiss Chemical Society (NSCS)

Stefan Pitsch*

Keywords: Eschenmoser, Albert· NSCS Spring Meeting 2000

The first meeting of the New Swiss ::, The meeting opened with a warm Chemical Society in this millennium was ~ welcome from H.L. Senti, President of a birthday present for one of our most ~ the NSCS, who was clearly gratified by prominent and esteemed members, Al- ~ this auspicious event. Donald Hi/vert bert Eschenmoser, who will soon cele- (ETH ZUrich) then summarized the life brate his seventy-fifth birthday. The work of Albert Eschenn19ser, which has meeting was held at the ETH Zurich encompassed investigations of the chem- (March 27th and 28th, 2000) in the form istry and biosynthesis of terpenes and of a symposium entitled 'Perspectives in steroids, insightful mechanistic studies of Chemistry and Chemical Biology'. This many fundamental chemical transforma- event gathered some of the most success- tions, synthesis of complex natural prod- ful and creative chemists of our time for ucts (including, notably, vitamin B 12 in two days of presentations honoring the collaboration with the late R.B. Wood- achievements of Professor Eschenmoser. ward!), and important contributions to prebiotic chemistry. By his keen intellect and through a deep understanding of chemical reactivity, Professor Eschen- moser has greatly influenced modern organic chemistry. Moreover, he has been a

'Correspondence: Dr. S, Pitsch great and charismatic teacher, inspiring laboratorium fUr Organische Chemie generations of chemists with his perspec- ETH-Zentrum tives on science. CH-8092 ZOrich Tel.: +41 1 6324481 The lecture portion of the symposium E-Mail: pitsch@org,chem,ethz.ch A. Eschenmoser was opened by M. Eigen (MPI ftir Bio- CONFERENCE REPORT 365

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The second lecture, entitled 'Ribonu- potential of enantioselective recognition cleotide Reductases: New Horizons', and product formation. was offered by J. Stubbe (MIT, Cam- bridge). Professor Stubbe has investigat- ed these proteins for many years, and her pioneering contributions have enabled deeper understanding of their fascinating mode of action. The ribonucleotide re- ductase-catalyzed deoxygenation of ribo- nucleotides is a premier example of a bio- logical process occurring via radical in- termediates, whose reaction cascades are so complex that their study is difficult. Impressively, Professor Stubbe demonstrated that methods related to organic chemistry, molecular biology, biochemis- try and spectroscopy allow characteriza- tion and quantification of exotic interme- diates, short-lived excited states and long-distance electron transfer processes.

H.L. Senti physikalische Chemie, G6ttingen) on the topic 'Molecular Diagnostics'. Professor Eigen demonstrated how the problem of detecting 'a single molecule among many J. Rebek. Jr. other molecules' has led to the development of new analytical tools with poten- The first day of the symposium was tially vast applications. Examples of such brought to a close by G.F. .Joyce (The applications range from detection of tiny Scripps Research Institute, La Jolla) who concentrations of virus, sequencing of presented surprising results from his lat- single DNA molecules, and early diagno- est work on 'The Influence of Chemical sis of the prion-induced Creutzfeld-Jacob Diversity on the Evolution of Catalytic disease. Development of these methods Function' .In contrast to proteins consist- was made possible through successful in- ing of twenty amino acids, catalytically tegration of chemistry, physics and bio- active ribozymes consist of only four nu- logy. cleosides which, additionally, contain but a very limited number of functional ~ groups. Professor Joyce has succeeded in ~" selecting and creating catalytically active :I: ribozymes with additional or fewer func- <; '"'0 tional groups, respectively. On the one 5: J. Stubbe hand, these studies demonstrate that the presence of additional functional groups After lunch and the NSCS general as- results in catalytically more active and/or sembly, the scientific program continued smaller ribozymes. On the other hand, with a lecture presented by 1. Rebek, Ir. catalytic activity can be achieved with ri- (The Scripps Research Institute, La Jol- bozymes consisting of 2'-deoxyribo- la). In 'Molecular Assembly and Encap- nucleotides or even of only three ribo- sulation', Professor Rebek demonstrated nucleotides. These experiments beauti- a straightforward approach to the crea- fully illustrate the catalytic potential of tion of tennis or softball-shaped mole- nucleic acid-related compounds. cules by self-assembly of appropriate The second day of the symposium building blocks. A variety of such struc- was opened by 'local matador' D. See- tures, offering cavities of different shape bach (ETH Zurich) who presented his and size, are able to encapsulate guest- latest achievements under the title 'The molecules and, therefore, can serve as re- Brave New World of I3-Peptides'. This action chambers. While some entropy- exciting lecture revealed that peptides as- driven reactions are significantly acceler- sembled from l3-amino acids are structur- ated by encapsulation, others are prevent- ally organized by secondary structure el- ed, Development of cavities with 'in- ements such as helices and sheets. These M. Eigen creasing asymmetry' bears the attractive elements are significantly more stable CONFERENCE REPORT 366

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r. provided an excellent overview of nu- ~ :I: merous research activities. As suggested ~ by the title 'Generating New Molecular ~ Function: A Lesson from the Immune System', the research program of Profes- sor Schultz is directed toward the study of molecular function and the creation of functional molecules. This focus was il- lustrated by pioneering contributions to the development of catalytic antibodies and by methods for incorporating unnatu- ral amino acids into proteins. Also presented were new base pairs based on hy- drophobic interactions, a theory about the G,F. Joyce molecular basis of the aging process, novel strategies for the creation of phar- than those found in the corresponding maceuticals by combinatorial substitu- natural analogues, 13-amino acids, More- tion of purines, and automated proce- over, a greater variety of peptide confor- dures for screening libraries and growing mations can be accessed simply by vary- single crystals. ing the substitution pattern within the constituent 13-amino acids. This novel class of molecules is stable towards peptidases and has an enormous number of potential applications, ranging from G.M. Whitesides new pharmaceuticals to new materials and new catalysts. 'Homologation of amino acids does not cause chaos but in- Following this series of exciting lec- creases structural order in peptides', stat- tures, C. Leumann (University of Bern) ed Professor Seebach. In this context, a addressed a few personal words to his 13-peptide inhibiting the uptake of choles- teacher Albert Eschenmoser. Lastly, in terol has already been found. the symposium's final speech, Professor The second lecture of the day was Eschenmoser himself thanked all lectur- held by P.G. Schultz (Novartis Institute ers individually for their outstanding confor Functional Genomics and The tributions to science today. Expressing Scripps Research Institute, La Jolla). It himself moved by this celebratory event, Professor Eschenmoser referred to the participants' research as 'evolutionary chemistry' . In summary, the New Swiss Chemical Society Spring meeting 2000 presented a most stimulating symposium reflecting P,G. Schultz some of the latest approaches and direc- tions in chemistry. Overall, this event The symposium's final lecture bore made a very strong statement on the im- the title 'Meso-Scale Self-Assembly', portance of inderdisciplinary research. and was presented by G.M. Whitesides Donald Hilvert (ETH Zi.irich) and Chris- (Harvard University, Cambridge). After tian Leumann (University of Bern) are to an amusing and deeply felt introductory be acknowledged and thanked for organ- address to Professor Eschenmoser, Pro- izing a most successful meeting. In clos- fessor Whitesides described a study in ing, we send you, dear Professor Eschen- which 'no molecules' were manipulated. moser, all sincere best wishes in your an- Instead of atoms and molecules, small, niversary year. We are very much looking sophisticated units were used to create forward to many continued achievements organized, complex structures by self-as- in chemistry and chemical biology. sembly. Instead of chemical bonds, capil- lary forces or 'sticky edges' cause adhe- Received: May 9, 2000 sion of these particles. These concepts clearly demonstrate fundamental princi- ples of chemistry and may be successful- ly used in teaching. As Whitesides point- ed out, applications of these small self- organizing structures also extend to mini- D. Seebach ature electronic devices.