A convenient synthesis of 4,8,9-trimethoxybenz[ <i>f</i> ] indenone, a potential BCD ring intermediate for stealthins and kinamycins†

994-996A convenient regiospecitic synthesis of 4,8,9- trimethoxybenz[ f ] indenone 6 has been developed which involves Hauser reaction between phthalide sulfone 3 and enone 4, followed by O-methylation of 5a and retro Diels-Alder reaction of 5b

A Representative Synthetic Route for C5 Angucycline Glycosides: Studies Directed toward the Total Synthesis of Mayamycin

This study discloses an efficient synthetic route for the regiospecific construction of a C5 glycoside angucycline representative of mayamycin. The key steps are intramolecular aldol condensation and Hauser annulation, and the key precursor for the aldol reaction is accessible through utilization of α-lithiation of a vinyl ether

Total Synthesis of Chlorocyclinone A, a PPAR‑γ Antagonist

The first total synthesis of chlorocyclinone A (<b>1</b>) is regioselectively completed in 28 steps. The key steps are Pd-catalyzed methoxycarbonylation, unprecedented Hauser annulation, Krohn photo-oxidation, and regioselective <i>gem</i>-dichlorination

Regiodefined synthesis of brominated hydroxyanthraquinones related to proisocrinins

Dibromobenzoisofuranone 12, synthesized in six steps, was regiospecifically annulated with 5-substituted cyclohexenones 13/36 in the presence of LiOt-Bu to give brominated anthraquinones 14/38 in good yields. Darzens condensation of 30 was shown to give chain-elongated anthraquinone 32. Alkaline hydrolysis of 38 furnished 39 representing desulfoproisocrinin F

Anionic Annulation of 3‑Cyanophthalides with Allene Carboxylates: A Carbon-Conserved Synthesis of Naphtho[<i>b</i>]furanones

The reaction of 3-cyanophthalides with allene carboxylates in the presence of ^<i>t</i>BuOLi results in a tandem annulation furnishing naphtho­[<i>b</i>]­furanones in good yields with no loss of carbon. The carbon economy is explained by a tandem process, in which the initially expelled cyanide induces the second annulation

Transpositive Tandem Annulation of Phthalides with Allene Carboxylates: Regioselective Synthesis of Arylnaphthalene Lignans

Allene carboxylates, scarcely used as Michael acceptors, serve as acceptors in the annulation with phthalides in the presence of LDA and provide a one-pot synthesis of naphtho­[<i>c</i>]­furanones in very good yields. This tandem annulation is proposed to proceed via transposition of the hydroxy group resulting from the initial annulation

Total Synthesis of Chlorocyclinone A, a PPAR‑γ Antagonist

The first total synthesis of chlorocyclinone A (<b>1</b>) is regioselectively completed in 28 steps. The key steps are Pd-catalyzed methoxycarbonylation, unprecedented Hauser annulation, Krohn photo-oxidation, and regioselective <i>gem</i>-dichlorination

Applications of [4+2] Anionic Annulation and Carbonyl-Ene Reaction in the Synthesis of Anthraquinones, Tetrahydroanthraquinones, and Pyranonaphthoquinones

Hexa-2,5-dienoates, susceptible to isomerization by acids and bases, are suitable for the [4+2] anionic annulation to give 3-(2-alkenyl)­naphthoates in regiospecific manner. When combined with intramolecular carbonyl-ene reaction (ICE), the accessibility of the naphthoates culminates in a new synthesis of anthraquinones and diastereoselective synthesis of tetrahydroanthraquinones. This strategy has also resulted in a 3-step synthesis of dehydroherbarin from a 3-methallylnaphthoate

Characterization of charge-transfer complex formation between 3, 6-diamino-9<i>H</i>-carbazole and 3,6-dinitro-9<i>H</i>-carbazole

271-276Electron donor-acceptor (EDA) interaction between 3,6-diamino-9H-carbazole (DAC) as the donor, and 3,6-dinitro-9H-carbazole (DNC) as the acceptor, has been characterized from IR spectral, differential scanning calorimetric (DSC), and X-ray diffraction analyses, in addition to UV-vis spectral studies. Benesi-Hildebrand plots of the DAC-DNC system in acetonitrile at 300 K in the wavelength range of 620-660 nm indicate a strong EDA interaction with both the thermodynamic formation constant K. and the molar absorptivity ελ. of the order of two. IR spectral, DSC, and XRD data also clearly indicate a strong EDA interaction even in their 1:1 molar mixture in solid state