01416nas a2200157 4500008004100000022001400041245021600055210006900271260007100340300001400411490000700425520065200432100002401084700001901108856013101127 2014 eng d a1523-706000aDiversity oriented convergent access for collective total synthesis of bioactive multifunctional carbazole alkaloids: synthesis of carbazomycin A, carbazomycin B, hyellazole, chlorohyellazole, and clausenaline D0 aDiversity oriented convergent access for collective total synthe a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a5470-54730 v163 a

Facile syntheses of imperative carbazole alkaloids carbazomycin A, carbazomycin B, hyellazole, chlorohyellazole, and clausenaline D have been demonstrated starting from readily available Boc-protected 3-formylindole and dimethyl maleate. The suitably substituted aromatic rings have been designed comprising three/four significant C-C bond forming reactions. The competent Wittig reaction, selective monoalkylations, one-pot regioselective Weinreb amide formation and Boc-deprotection, well designed Grignard reactions, dehydrative intramolecular cyclizations, and Baeyer-Villiger rearrangement of aromatic aldehydes were the main features.

1 aMarkad, Shivaji, B.1 aArgade, N., P. uhttps://library.ncl.res.in/content/diversity-oriented-convergent-access-collective-total-synthesis-bioactive-multifunctional-001352nas a2200157 4500008004100000022001400041245016500055210006900220260007100289300001400360490000700374520065200381100002401033700001901057856011801076 2016 eng d a0022-326300aBiomimetic collective total synthesis of bioactive carbazole alkaloids indizoline, mafaicheenamine A, claulamine A, claulansine A, and the proposed claulamine E0 aBiomimetic collective total synthesis of bioactive carbazole alk a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN a5222-52270 v813 a

The common precursor 1-methoxy-2-prenyl-3-carbomethoxycarbazole was synthesized from dimethyl indolylmethylenesuccinate in four steps. Well-planned reductive and/or oxidative transformations and intramolecular cyclizations were performed on a pivotal common precursor to accomplish collective first total synthesis of titled natural products and proposed Claulamine E. Burgess reagent induced formation of kinetically controlled product Claulamine A, and intramolecular cyclizations to form bicyclic claulansine A were the key reactions. An alternatively attempted synthesis failed to provide the structural isomer of proposed Claulamine E.

1 aMarkad, Shivaji, B.1 aArgade, N., P. uhttps://library.ncl.res.in/content/biomimetic-collective-total-synthesis-bioactive-carbazole-alkaloids-indizoline01487nas a2200157 4500008004100000022001400041245019400055210006900249260000800318300001200326490000700338520082400345100002401169700001901193856011701212 2018 eng d a0022-326300aSolid state auto-inversion of C-centrochirality: enantioselective total synthesis of furocarbazolones (-)-epi-claulansine D and (-)-claulansine D and pyranocarbazolone (+)-epi-claulansine C0 aSolid state autoinversion of Ccentrochirality enantioselective t cJAN a382-3870 v833 a

Starting from dimethyl (E)-2-{[(1-tert-butoxycarbonyl)-1H-indol-3-yl]methylene}succinate and (R)-2,2,5,5-tetramethyl-1,3-dioxolane-4-carbaldehyde, facile synthesis of (-)-epi-claulansine D was accomplished via condensation and two intramolecular cyclizations. The (-)-epi-claulansine D in the solid state exists in a metastable form, and after an induction period of 30-90 days, it underwent complete epimerization to exclusively deliver the desired natural product (-)-claulansine D in quantitative yield. The witnessed inversion of C-centrochirality in the solid state is conceptually novel and takes place for relatively higher crystal stability reasons. Base-catalyzed ring expansion of both (+/-)/(-)-epi-claulansine D and (+/-)/(-)-claulansine D resulted in (+/-)/(+)-epi-claulansine C in very good yields.

1 aMarkad, Shivaji, B.1 aArgade, N., P. uhttps://library.ncl.res.in/content/solid-state-auto-inversion-c-centrochirality-enantioselective-total-synthesis