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Carbohydrate Chemistry

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					                                             Carbohydrate Chemistry

Synthetic Carbohydrate Chemistry: Glycoside synthesis, preparative studies of
antibiotic and cytostatic oligosaccharides, synthesis of complex saccharide conju-
gates, preparations of carbohydrate mimetics, photochemical transformation of car-
                                                                                          Prof. Dr. Joachim Thiem
bohydrate derivatives.

Preparative Chemoenzymatic Synthesis: Application of glycohydrolases and gly-
cosyltransferases for synthesis of oligo- saccharides, use of further enzyme systems
for preparative purposes.

Carbohydrates as Chemical Feedstock: Studies on the synthesis of polymers
(polyesters, -urethanes, -ethers, -amides) from saccharide building units, work in the
field of saccharide based surfactants.


         Recent Examples                      ously glycosylated natural products
Synthetic Carbohydrate Chemistry:             such as steroids and tocopherols. In
                                              further studies we also deal with combi-
In this area we are involved in a number      natorial glycosylations. Some other        Institut für Organische Chemie
of different projects. Some are con-          work centered on carbohydrate mimet-       Universität Hamburg
cerned with methodology studies in gly-       ics employing sigmatropic rearrange-       Martin-Luther-King-Platz 6,
cosylation, e.g. we are elaborating           ments of saccharide-derived allyl          20146 Hamburg
applications for the synthesis of vari-       ketene acetals (Fig. 1) [1].
                                                                                         E-Mail: thiem@chemie.uni-
                                                                                         hamburg.de
                                                                                         Telefon: +49-(0)40-42838 4241
                                                                                         Telefax: +49-(0)40-42838 4325

                                                                                         Curriculum:
                                                                                         Chemistry study and Dissertation in
                                                                                         Hamburg with Prof. Dr. H. Paulsen
                                                                                         (1972); Habilitation (1978) and Assis-
                                                                                         tant Prof. in Hamburg (till 1982);
                                                                                         Associate Prof. in Münster (1983-
                                                                                         1989); Full Prof. in Hamburg (since
                                                                                         1989); Sabbaticals and Visiting Pro-
                                                                                         fessorships: University of California,
                                                                                         Berkeley,CA, USA (1984/85), Victoria
                                                                                         University and IRL, Wellington, NZ
                                                                                         (1993); CERMAV, Grenoble, F (1995).
Figure.1: Carbohydrate mimetics employing sigmatropic rearrangements of saccharide-      Scripps Research Institute (TSRI), La
derived allyl ketene acetals [1].                                                        Jolla, CA, USA (2005/06).

                                                                                         Public Service:
                                                  Preparative Chemoenzymatic             German Representative in European
                                                            Synthesis                    Carbohydrate Organisation (since
                                                                                         1987) and International Carbohydrate
                                              Here we perform enzymatic synthesis        Organisation (since 1990); Member
                                              employing efficiently available enzymes    of Executive Board FEI (since 1989);
                                              of the carbohydrate metabolism. In con-    Confidential Docent of FCI (since
                                              trast to the analytical biochemical        1991); Member of Scientific Work-
                                              approach focus is rather on the prepar-    group of Industrial Research Comitee
                                              ative aspect. With much success hydro-     (since 1991). Speaker of Collabora-
                                              lases can be used for synthesis in the     tive Research Grant (SFB 470) „Gly-
                                              sense of transglycosylations [2]. Also     costructures in Biosystems - Synthe-
                                              glycosyltransferases could be employed     sis and Impact“ (since 1997); Dean
                                              most efficiently giving rise to complex    Department of Chemistry 04/2002 –
                                              heterooligosaccharides [3]. Recently       10/2005.
                                              the unusual trans-sialidase could be
                                              expressed in E.coli and used in the syn-   Auszeichnungen:
                                              thesis of a-2-3 sialylated oligosaccha-    Heyrovsky Medaille 2001 der Tsche-
                                              rides (Fig.2 [4].                          chischen Akademie der Wissen-
                                                                                         schaften.




                                                     Chemiedozententagung 2006                                            49
           Carbohydrates as
          Chemical Feedstock

Formation of saccharide derived poly-
mers requires avoiding the typical pro-
tecting group chemistry known for car-
bohydrate derivatives. We have realized
the preparation of many polymers of
interest such as polyesters, polyureas,
polyurethane, polyamides and poly-
ethers. Recently, novel polyglycosilox-
anes with interesting properties could
be obtained by hydrosilylation of carbo-
hydrate precursors (Fig.3) [5].


 References
 [1] S. Jürs, J. Thiem, Tetrahedron Asymm., 16,
     1631-1638 (2005).
 [2] L. Kröger, J. Thiem, J. Carbohydr. Chem.
     24, 717-722 (2005)
 [3 A. M. Scheppokat, H. Bretting, J. Thiem,
     Carbohydr. Res., 338, 2083-2090 (2003).
 [4] B. Neubacher, D. Schmidt, P. Ziegelmüller,
     J. Thiem, Org. Biomol. Chem. 3, 1551-        Figure 2: Use of recombinant trans-sialidase (T. cruzi) for a-2-3 sialylation of D-Gal-terminat-
     1556 (2005).
                                                  ed oligosaccharides [4].
 [5] D. Henkensmeier, B. C. Abele, A. Candus-
     sio, J. Thiem, Macromol. Chem. Phys., 205,
     1851-1857 (2004).




Figure 3: General reaction pattern; X is a carbohydrate moiety, Mn (PDMS-H2) = 592 g/mol [5].




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     50                                                  Chemiedozententagung 2006

				
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