Divergent Approach to the Bisanthraquinone Natural Products: Total Synthesis of (S)-Bisoranjidiol and Derivatives from Binaphtho-para-quinones

Abstract

The development of the first asymmetric synthesis of a chiral anthraquinone dimer is outlined, resulting in the first total synthesis of (S)-bisoranjidiol. Rather than a biomimetic dimerization retrosynthetic disconnection, the anthracenyl ring systems are generated after formation of the axially chiral binaphthalene framework. This synthetic strategy has enabled the synthesis of several analogs. Key features of the synthesis include the enantioselective coupling of a hindered 2-naphthol containing substitution peri to the site of C-C bond formation, the regioselective oxidation of 8,8′-hydroxylated binaphthols to binaphtho-para-quinones, and a tandem regioselective Diels-Alder/aromatization reaction.

Light-Mediated Reductive Debromination of Unactivated Alkyl and Aryl Bromides

“…Synthetic chemists utilize bromine as a directing group in many contexts, including electrophilic aromatic substitutions, Diels–Alder reactions, and the Bartoli indole synthesis, which stand to benefit from a mild, efficient approach for cleaving carbon–bromide bonds. Traditional methods for the reduction of carbon–bromide bonds proceed through metal–halogen exchange, hydride reduction, atom transfer, or single-electron reductions .…”

Charge-Transfer Complexes of Linear Acenes with a New Acceptor Perfluoroanthraquinone. The Interplay of Charge-Transfer and F···F Interactions

“…Perfluoroanthraquinone was first studied in 1973 with visual registration of the reflections’ intensity; thus, we decided to redetermine its crystalline structure using modern facilities and low temperature. The notable feature of the PFAQ molecule is the folded structure of its carbon skeleton (Figure ); two planes involving terminal aromatic rings intersect along the central C–C direction with the torsion angle 19.7°, in contrast to planar anthraquinone − or some of its derivatives with hydroxyl groups attached to carbons at 1 or 8 positions. − This distortion of planarity is caused by the repulsion between the oxygen atoms and the neighboring fluorine atoms, which results in unusual conformation of the quinone ring. The central six-membered quinone ring adopts the boat conformation with carbon atoms bearing oxygens deviating from the plane of the other four carbons.…”

Recent advances in oxidative phenol coupling for the total synthesis of natural products

“…In a follow-up publication, divergent syntheses of this framework were achieved to furnish bisanthraquinone analogues (not shown). 69 In 2007, a research group from the University of Mississippi isolated a marine natural product from the Indonesian sponge Lendenfeldia sp. and determined its structure to be (S)-11 via NMR analysis.…”

“…In a follow-up publication, divergent syntheses of this framework were achieved to furnish bisanthraquinone analogues (not shown). 69…”