Toluene-Dioxygenase-Mediated cis-Dihydroxylation of Aromatics in Enantioselective Synthesis. Iterative Glycoconjugate CouplingStrategy and Combinatorial Design for the Synthesis of Oligomers of nor-Saccharides,Inositols and Pseudosugars with Interesting Molecular Properties

The authors wish to dedicate this article to the memory of Professor WolfgangOppolzer, who passed away on March 15, 1996. Professor Oppolzer’s contributionsto the art and craft of organic synthesis and his energetic career were cutshort by this untimely tragedy, which has left a serious void in the syntheticcommunity. His intellectual capacity and his style of problem solving servedas an example and inspiration to many of us. Tomas Hudlicky was a postdoctoralfellow in Geneva during the early years of Professor Oppolzer’s academiccareer. He credits much of this success as an independent investigator tothe mentorship he received in 1977-78 from Professor Oppolzer; he is deeplyaffected by the loss of one of the great practitioners. Vinyl epoxides 18 Caret and 31 and vinylaziridines 24and 25 derived from chloro- or bromocyclohexadiene-cis-diols 9 have been condensed with protected cyclitols 19, 37, and 46 in an iterative manner to generate dimeric,trimeric and tetrameric conduritol or aminocyclitol conjugates which on furtherfunctionalization of the olefins and deprotection yielded inositol conjugates 22, 53, and 59 and aminocyclito conjugates 30, 36 and 45. Iodocyclohexadiene-cis-diol 71 and methyl shikimate 82 were used as synthons for thesynthesis of pseudo-β-D-glucopyranose 85 and pseudo-α-L-mannopyranose 86 as well as the C6-linkes dimer 81. The X-ray structureof dimer 30 with calcium has shown interesting molecular propertiesand cell-assembly. Molecular modeling of the higher oligomers has shown atendency toward secondary β-turn characteristics foundin polypeptide chains such as L-proline octamers. Based on the metal-chelatingability of some of the conjugates and the interesting secondary structuralproperties of L-chiro-inositol oligomers futuredirection of this research in the area of molecular recognition and combinatorialsynthesis are postulated.

inositol conjugates - biooxidation - toluene dioxygenase - calcium chelation - helical structure