title: Regio- and Stereoselective Functionalization of 16-Membered Lactone Aglycone of Spiramycin via Cascade Strategy.
abstract: Functionalization of 16-membered aglycone of spiramycin with the use of intramolecular cascade strategy yielded access to novel types of diastereopure bicyclic spiramycin derivatives containing tetrahydrofuran ring. Experimental results shows that a specific sequence of regio- and stereoselective transformations, based on the intramolecular transesterification, E1cB tandem eliminations, 1,2-addition to carbonyl, and 1,6-conjugate addition at the spiramycin aglycone, proceeds with the inversion of absolute configuration at C(5) stereogenic center. Performed cascade and multistep transformations have opened new possibilities in divergent modifications, not only spiramycin but also the whole family of leucomycin type antibiotics having a similar structure of 16-membered aglycone lactone ring.
authors.affiliation: Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Klich
authors.affiliation: Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland.
authors.forename: Krystian
authors.initials: K
authors.lastname: Pyta
authors.affiliation: Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Przybylski
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D007783:Lactones / Q000737:chemistry*; D015572:Spiramycin / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D013302:Streptomyces / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D007783:Lactones; D015572:Spiramycin