title: Stereoselective total synthesis of (-)-spirofungin A by utilising hydrogen-bond controlled spiroketalisation.
abstract: The stereoselective total synthesis of the spiroketal containing Streptomyces metabolite (-)-spirofungin A (1) is described. A key step involved a spiroketalisation controlled by an intramolecular H-bond which favoured the desired spiroketal 4 (13:1 ratio). The presence of the intramolecular H-bond in 4 is possibly due to a 1,5-alkyne-oxygen interaction. Other key steps include an efficient cross-metathesis to form the spiroketal precursor, a tin mediated syn-aldol reaction and a Stille cross-coupling reaction to create the C22C23 bond. A final Wittig extension followed by deprotection gave (-)-spirofungin A (1).
authors.affiliation: School of Chemistry, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia.
authors.forename: John E
authors.initials: JE
authors.lastname: Lynch
authors.forename: Shannon D
authors.initials: SD
authors.lastname: Zanatta
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
authors.forename: Mark A
authors.initials: MA
authors.lastname: Rizzacasa
mesh_terms: D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D006860:Hydrogen Bonding; D015394:Molecular Structure; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013302:Streptomyces / Q000737:chemistry*
chemical_list: D005663:Furans; D011714:Pyrans; D013141:Spiro Compounds; C114877:spirofungin A; C493365:spirofungin B; C520774:spiroketal