title: Synthesis of bisbenzannulated spiroketals-model studies for a modular approach to rubromycins.
abstract: [reaction: see text] A highly flexible synthesis of bisbenzannulated spiroketals is described with additions of lithiated methoxyallene to aryl aldehydes and Heck reactions as key steps. Subsequent hydrogenations and ketalizations afforded the desired spiroketals in good yields and with predominating trans-configuration. With model compound 30, already bearing the fully substituted naphthyl core of rubromycins, the ketalization proceeded efficiently providing the expected product 31 and the isopropoxy compound 32. Both products are advanced model compounds of heliquinomycin.
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Sörgel
authors.forename: Cengiz
authors.initials: C
authors.lastname: Azap
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Reissig
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry; D011809:Quinones / Q000138:chemical synthesis* / Q000737:chemistry; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D016227:Benzoquinones; D009281:Naphthalenes; D011809:Quinones; D013141:Spiro Compounds; C101772:heliquinomycin; C064949:gamma-rubromycin