One-step preparation of xanthones via Pd-catalyzed annulation of 1,2-dibromoarenes and salicylaldehydes

Wang, Sizhuo; Xie, Ke; Tan, Ze; An, Xiangyu; Zhou, Xinmei; Guo, Can‐Cheng; Peng, Zhihong

doi:10.1039/b913951f

Cited by 32 publications

(11 citation statements)

References 51 publications

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“…The xanthone derivatives are the core structure of many natural compounds and pharmaceuticals and, at the same time, they are versatile synthons to achieve new heterocycles. Most of the known methods for their synthesis either require rather complicated and/or expensive starting materials or involve multistep transformations by using different catalysts . In our case the formation of 11 can be explained by the mechanism depicted in Scheme .…”

Section: Resultsmentioning

confidence: 99%

Ortho‐Quinone Methide Driven Synthesis of New O,N‐ or N,N‐Heterocycles

et al. 2019

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To synthesize functionalized Mannich bases that can serve two different types of ortho ‐quinone methide ( o ‐QM) intermediates, 2‐naphthol and 6‐hydroxyquinoline were reacted with salicylic aldehyde in the presence of morpholine. The Mannich bases that can form o ‐QM and aza ‐ o ‐QM were also synthesized by mixing 2‐naphthol, 2‐nitrobenzaldehyde, and morpholine followed by reduction of the nitro group. The highly functionalized aminonaphthol derivatives were then tested in [4+2] cycloaddition with different cyclic imines. The reaction proved to be both regio‐ and diastereoselective. In all cases, only one reaction product was obtained. Detailed structural analyses of the new polyheterocycles as well as conformational studies including DFT modelling were performed. The relative stability of o ‐QMs/ aza‐o ‐QM were also calculated, and the regioselectivity of the reactions could be explained only when the cycloaddition started from aminodiol 4 . It was summarized that starting from diaminonaphthol 25 , the regioselectivity of the reaction is driven by the higher nucleophilicity of the amino group compared with the hydroxy group. 12H‐benzo[a]xanthen‐12‐one ( 11 ), formed via o ‐QM formation, was isolated as a side product. The proton NMR spectrum of 11 proved to be very unique from NMR point of view. The reason for the extreme low‐field position of proton H‐1 could be accounted for by theoretical calculation of structure and spatial magnetic properties of the compound in combination of ring current effects of the aromatic moieties and steric compression within the heavily hindered H(1)‐C(1)‐C(12b)‐C(12a)‐C(12)=O structural fragment.

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Section: Resultsmentioning

confidence: 99%

Ortho‐Quinone Methide Driven Synthesis of New O,N‐ or N,N‐Heterocycles

et al. 2019

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“…The reaction was carried out by stirring the dibromoarene (2 equiv) with the salicylaldehyde (1 equiv) in N,N-dimethylformamide at 130°C in the presence of dichlorobis(triphenylphosphine)palladium(II) (5 mol%) as catalyst and potassium carbonate (2 equiv) as base (Scheme 91). 201 Both methyl and methoxy groups were tolerated on the salicylaldehyde, furnishing the desired xanthones in good yields (52-63%). However, when a strong electron-donating group, such as diethylamino, was introduced, the yield was lower (38%).…”

Section: Scheme 90mentioning

confidence: 98%

Recent Developments in Palladium-Catalyzed Formation of Five- and Six-Membered Fused Heterocycles

Majumdar¹,

Samanta²,

Sinha³

2012

Synthesis

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Palladium-mediated cyclization reactions have been recognized as some of the simplest and useful tools for regio-as well as stereoselective syntheses of carbo-and heterocyclic compounds. In the multi-step syntheses of natural products it is frequently used as one of the most important steps. In this review article, we have summarized the various ways of constructing five-and six-membered heterocyclic rings by palladium-catalyzed intramolecular cyclizations published between 2008 and 2010.

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“…The reaction was performed in toluene under reflux conditions. 1,2‐Dibromobenzene can react with salicylaldehyde in DMF at 130 °C with the aid of PdCl 2 (PPh 3 ) 2 catalyst, providing xanthone 58 in generally good yields in the presence of 2.0 equivalents of K 2 CO 3 (Scheme ) …”

Section: Benzaldo‐x Bifunctional Building Blocks and Their Heterocyclmentioning

confidence: 99%

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

Ravichandiran

Lai

2016

The Chemical Record

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Compounds containing oxygen, nitrogen, or sulfur atoms inside the rings are attracting much attention and interest due to their biological importance. In recent years, several methods for the synthesis of such molecules have been reported by using aldo-X bifunctional building blocks (AXB3 s) as substrates; these are a wide class of organic molecules that contain at least two reactive sites, among them, one aldehyde, acetal, or semiacetal group was involved. Because of the multiple reactivities, AXB3 s are widely used in the one-pot synthesis of biologically important heterocycles. This review summarizes the synthesis of important heterocycles by using AXB3 s as pivotal components in establishing multicomponent reactions, tandem reactions, and so forth. In many cases, the established reaction systems with AXB3 s were characterized by some green properties, such as easy access to the substrate, mild and environmentally benign conditions, and wide scope of the substrate.

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One-step preparation of xanthones via Pd-catalyzed annulation of 1,2-dibromoarenes and salicylaldehydes

Abstract: A one-step preparation of xanthones via Pd-catalyzed annulation of 1,2-dibromoarenes and salicylaldehydes was developed.

Cited by 32 publications

References 51 publications

Ortho‐Quinone Methide Driven Synthesis of New O,N‐ or N,N‐Heterocycles

Ortho‐Quinone Methide Driven Synthesis of New O,N‐ or N,N‐Heterocycles

Recent Developments in Palladium-Catalyzed Formation of Five- and Six-Membered Fused Heterocycles

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

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