The Peak of Stereochemistry:B�rgenstock 2004

Rolf Breinbauer

The B�rgenstock is a peak 500 m abovepicturesque Lake Lucerne in Switzer-land. The ensemble of hotels steepedin tradition at the top provides a splen-did setting for one of the most presti-gious conferences in chemistry: the B�r-genstock Conference on Stereochemis-try, which took place in April for the39th time.

A peculiarity of this conference isthat the program is not announced inadvance. The speakers are invited bythe conference president—this yearHerbert Waldmann (Dortmund, Ger-many)—and the Switzerland-basedorganizing committee: Hans-BeatB�rgi (Universit0t Bern), Fran2ois Die-derich (ETH Z�rich), Ernst PeterK�ndig (University of Geneva), andKlaus M�ller (Roche, Basel). Themore than 130 participants from aca-demic institutions and industry theworld over were informed about theschedule after registration at the hotelreception.

The scientific program began onSunday with a talk by Roger S. Goody(Max-Planck-Institut (MPI) Dort-mund). In his lecture he presented struc-tural and mechanistic aspects of the reg-ulation of vesicular transport by RabGTPases. By using a combination ofkinetic studies, chemical biologicaltools, and X-ray crystal-structure analy-sis of protein complexes, his researchgroup has been able to elucidate severalimportant elements of vesicular trans-

port. Ilme Schlichting (MPI Heidelberg)followed with a discussion on how thereactivity of heme proteins is controlledthrough their molecular architecture. Byusing time-resolved protein X-ray crys-tallography she could characterize sev-eral intermediates in the catalytic oxida-tion cycles of cytochrome P450(Figure 1) and nitric oxide synthases(NOS). The evening lecture was pre-sented by Michel Rohmer (UniversityLouis Pasteur, Strasbourg), whose stud-ies have shown that isoprenoids are notonly biosynthesized through the meval-onate pathway, but that in chloroplasts,green algae, and several eubacteria analternative methyl erythritol phosphate(MEP) pathway exists.

On Monday morning, the partici-pants were greeted by heavy snowfalland an informative talk by JonathanEllman (University of California (UC),Berkeley) on the use of tert-butylsulfinylimines as powerful reagents for thepreparation of substituted aminesthrough C�C bond formation. Further-more, he described how heteroatom-directed C�H activation can be carriedout enantioselectively. Matthias Beller(Leibniz-Institut f�r Organische Kataly-seforschung, Rostock, Germany) re-ported on a variety of new or optimizedcatalytic processes, such as amidocarbo-nylation, Ar�X activation, hydroamina-tion, cyanation, and tandem isomeriza-

tion–hydroamination reactions. Nicho-las Leadbeater (University of Connecti-cut, Storrs, USA) gave an introductionon “orgaNOmetallic” reactions. Suzukiand Sonogashira reactions can be car-ried out even in the absence of ametal, as careful mechanistic studieshave proven. Milton R. Smith III (Mich-igan State University, East Lansing,USA) showed that an Ir–phosphanecomplex enables the meta-selective sub-stitution of even substituted arenes withboronic acid moieties in high yields andhigh catalyst turnovers through C�Hactivation. In the final lecture of theday Matthew D. Shair (Harvard Univer-sity) presented an elegant synthesis oflongithorone A, which was inspired bynature and features inter- and intramo-lecular Diels–Alder reactions and anenyne macrocyclization. His researchgroup has also successfully carried outa biomimetic enantioselective aldolreaction starting from malonic acidequivalents.

On Tuesday Atsuhiro Osuka (KyotoUniversity) demonstrated that por-phyrin derivatives can be made toundergo oxidative oligomerization in acontrolled manner to form micrometer-long entities. These materials could notonly be characterized but also possessexciting electronic and optical proper-ties. Harry Anderson (Oxford Univer-sity, UK) showed that p systems can be

Figure 1. The active center of cytochrome P450 monooxygenases resembles a blowtorch. Theheme-bound active oxygen species is able to hydoxylate even non-activated hydrocarbons. Thefigure shows the active site of cytochrome P450cam, which catalyzes the 5-exo-hydroxylation ofcamphor (green). Kindly made available by Daniel Peisach, Department of Biological Chemistry,University of Michigan, Ann Arbor, USA.

[*] R. BreinbauerMax-Planck-Institut f0r molekulare Physio-logie und Universit1t Dortmund (Germany)E-mail: rolf-peter.breinbauer@mpi-dort-

mund.mpg.de

Meeting Reviews

2988 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/anie.200460496 Angew. Chem. Int. Ed. 2004, 43, 2988 – 2989

insulated by rotaxane formation. Forexample, a cyclodextrin/azo dye/rotax-ane species does not undergo photo-bleaching, whereas the unprotecteddye does.

On the following day Kazunari Taira(University of Tokyo) described severalimportant applications of ribozymes.For example, he discussed the design ofallosterically controllable ribozymes,the identification of genes by hybridribozymes, and a new type of RNAinterference (shRNA), whereby evenlong RNA strands fail to induce animmune response. Michael Famulok(Universit0t Bonn, Germany) explainedhow intracellular aptamers (“intra-mers”) can be used as a tool in chemicalgenetics. With a highly selective intra-mer he could differentiate between thebiological functions of the highly homo-logous proteins cytohesin 1 and 2.Kevan Shokat (UC, Berkeley and UC,San Francisco) presented an ingeniousapproach for deciphering kinase signaltransduction, whereby small-moleculecompounds were used to control geneti-cally modified proteins. With thismethod he could demonstrate that kin-ases act synergistically to produce

unique phenotypes that do not occurwith monoinhibition.

The last day of the conferencestarted with a talk by Henk Hiemstra(Amsterdam University) on the prog-ress his research group has madetowards the total synthesis of solanoe-clepin A. This natural product featuresa complex arrangement of three- toseven-membered rings, many of whichhave already been assembled toadvanced fragments by his group.Larry Overman (UC, Irvine) presentedelegant solutions to one of the most dif-ficult problems in organic synthesis: theasymmetric construction of quaternarycarbon stereocenters. Methodologybased on Heck and diastereoselectivedialkylation reactions enabled hisresearch group to synthesize a series ofchallenging polypyrrolidinoindolinealkaloids. The privilege of holding thelast lecture was given to an inorganicchemist: Karl Wieghardt (MPI M�l-heim, Germany) explained in his talkentitled “Coordination chemistry oflife” how his research group prepareda variety of inorganic models of theCu–tyrosinyl enzyme galactose oxidaseand ultimately discovered a catalyst

that mediates the oxidation of primaryalcohols by oxygen. He also describedhow inorganic models of the Mn clusterin photosystem II have helped in thecharacterization of several catalyticintermediates in the water oxidationreaction. Klaus M�ller closed the con-ference with his traditional wittyreview of events: a summary of the sci-ence presented, spiced up with somepersonal observations.

The balanced schedule of the confer-ence and the indescribable beauty of itslocation were conducive not only toextensive scientific discussions, but alsoto social networking and sporting activi-ties. Supported by their national societ-ies, 20 young European scientists wereable to participate in this conferenceand present their work at the twoposter sessions. The 40th B�rgenstockconference (April 16–22, 2005) will bechaired by the new president AlainKrief (Namur, Belgium), whose dutythis year as vice president was “to takecare of the weather”. His masterfulaccomplishment of this important taskraises expectations for the next confer-ence.

AngewandteChemie

2989Angew. Chem. Int. Ed. 2004, 43, 2988 – 2989 www.angewandte.org 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim