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

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

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

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

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

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

Studies directed toward total synthesis of rhodocomatulins: A regioselective synthesis of brominated hydroxyanthraquinones by anionic annulations

<p>In this work, brominated hydroxyanthraquinones, which are the core structural motif of naturally occurring bromorhodocomatulins, were successfully synthesized using Hauser annulation reaction as the key step. When brominated Michael acceptors (brominated <i>p</i>-quinone monoketals) and cyanophthalides or bromocyanophthalides (Hauser donors) were reacted under the annulation conditions, brominated anthraquinones were obtained with 81–87% yields for four examples. On acidic quenching, products were obtained as solid which were separated by filtration and purified by recrystallization in acetone. No chromatography was required.</p

Synthesis of Vitamin K and Related Naphthoquinones via Demethoxycarbonylative Annulations and a Retro-Wittig Rearrangement

Anionic annulations of 3-nucleofugal phthalides with α-alkyl­(aryl)­acrylates involving a demethoxycarbonylation provide a succinct synthesis of vitamin K and related naphthoquinones. Also reported is a new cascade reaction stemming from a Cope–retro-Wittig rearrangement. This cascade leads to direct formation of 1-hydroxy-4-prenyloxynaphthalene-2-carboxylates from the corresponding α-prenyl acrylate acceptors

Angucycline C5 Glycosides: Regio- and Stereocontrolled Synthesis and Cytotoxicity

This study discloses a general and convergent route for the regio- and stereospecific construction of the C5 glycosyl angucycline framework of mayamycin. <i>C</i>-Glycosidation, dearomatization, and Hauser annulation are the key steps. The synthetic analogues show cytotoxicity against different human cancer cell lines with IC₅₀ values between 16.4 and 1.2 μM