Syntheses of the Fungal Metabolites Boletopsins 7, 11, and 12 from the Papua New Guinea Medicinal Mushroom Boletopsis sp.

Abstract

Boletopsins 7 (1), 11 (2), and 12 (3) are p-terphenyl dibenzofuran compounds, isolated from the Papua New Guinean medicinal mushroom Boletopsis sp. The first syntheses of these fungal metabolites are reported, allowing for an investigation of their antibiotic activity. The key steps include sequential Suzuki-Miyaura couplings to rapidly form the p-terphenyl backbone and an Ullmann ether synthesis on a formate ester to create the dibenzofuran moiety. Biological evaluation of the synthetic compounds and intermediates against a panel of bacterial nosocomial pathogens was performed.

Photoinduced Synthesis of Dibenzofurans: Intramolecular and Intermolecular Comparative Methodologies

“…13 C NMR (100 MHz, (CD 3 ) 2 CO) δ 157.4 (q, C−O); 155.2 (q, C−O); 147.0 (q); 128.0 (C Ar −H); 126.0 (C Ar −H); 125.4 (q); 124.6 (q); 123. 6 13 C NMR (100 MHz, (CD 3 ) 2 CO) δ 156.9 (q, C−O); 153.4 (q, C−O); 146.7 (q); 134.8 (q); 127.7 (C Ar −H); 125.4 (q); 125.0 (q); 123. Dibenzo[b,d]furan-2-carbonitrile (1g).…”

“…The dibenzofuran nucleus provides chemical characteristics that enable it to position itself as a versatile molecule in different fields of chemical research. Different potential applications have been studied, such as anticancer, , antioxidant, antibacterial − and as enzyme inhibitors. , In addition, substituted dibenzofurans have been used in the development of OLED …”

Sequential and iterative Pd-catalyzed cross-coupling reactions in organic synthesis

“…Both groups used the same substrate and coupled selectively the bromide in ortho -position to the carbaldehyde in the first coupling step (Scheme 18). The electronic influence of the substituents was sufficient to couple selectively the more electron-deficient position first [32, 33].

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Microwave‐Promoted Pd‐Catalyzed Synthesis of Dibenzofurans from Ortho‐Arylphenols

“…In routes c and d, biaryl compounds 4 and 5 are used as starting materials and the dibenzofuran formation is completed by an etherification. Biaryls 4 , substituted with a leaving group in the 2′ position, can undergo cyclization via a base‐mediated S NAr pathway , a copper mediated or catalyzed Ullmann‐type reaction , or a Pd‐catalyzed O ‐arylation. The latter method, developed by Buchwald and coworkers for the intermolecular synthesis of diaryl ethers has later been expanded to the synthesis of dibenzofurans from biaryls 4 .…”