Oxidative Biaryl Coupling Reaction of Phenol Ether Derivatives Using a Hypervalent Iodine(III) Reagent

Abstract

The hypervalent iodine(III)-induced intramolecular biaryl coupling reaction of phenol ether derivatives (nonphenolic derivatives) was investigated with the aim of preparing various dibenzo heterocyclic compounds. 1,3-Diarylpropanes (1a-e), N-benzyl-N-phenethylamines (2a-c) and N,Ndibenzylamines (3a-e) react with a hypervalent iodine reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA), containing BF 3 ‚Et 2 O in CH 2 Cl 2 to give the biaryl coupling products (4-6) in good yield. As an application of the reaction, we examined the synthesis of oxygen-and sulfur-containing dibenzoheterocyclic compounds (12-15), whose side chain moiety could be easily cleaved by the known method to give 2,2′-substituted biphenyl compounds (16-18).

Photocatalytic green synthesis of piperonal in aqueous TiO2 suspension

“…Column chromatography with petroleum/ethyl acetate 5:1 allowed to obtain the 1,3-bis(3,4-(methylenedioxy)benzyl) ether (102 mg, 43% yield). The identity of the synthesized 1,3-bis(3,4-(methylenedioxy)benzyl) ether was confirmed by 1 H, 13 C NMR, and MS spectroscopy and it exactly matches what reported in the literature [29]. 1 (15).…”

Reactions of 1-Naphthols with .PI.-Acceptor p-Benzoquinones: Oxidative Aryl Coupling vs. Non-Oxidative Electrophilic Arylation

“…4) Oxidizing reagents used in the oxidative coupling reaction of hydroxyarenes include a variety of metal salts, 16) Lewis acids 17,18) and nitrosonium salts, 19) and hypervalent iodine-(III) reagents. 20) Recently, in particular, various oxidizing reagent systems for the coupling of 2-naphthols by using combinations of metal salts or metal complexes as a catalyst with aerial oxygen or dioxygen (O 2 ) have been developed: these catalysts include FeCl 3 -SiO 2 , CuSO 4 -Al 2 O 3 , CuSO 4 montmorillonite, CuCl-amine complexes, CuCl(OH)-TMEDA, and oxovanadium(IV) complexes. 22) However, the choice of a suitable reagent for the synthesis of particular desired biaryls is still largely empirical.…”

Development and Application of New Oxidation Systems Utilizing Oxometalate Catalysts

“…Thus reaction of norbelladine derivative 1p with the previously described PhI(OCOCF 3 ) 2 -BF 3 ·Et 2 O reagent system in CH 2 Cl 2 gave the biaryl (Table 5, entry 1). 94) On the other hand, reaction of 1p with the present PhI(OCOCF 3 ) 2 -HPA reagent system in CH 3 CN afforded spirodienone 3p in 46% yield (entry 2). Exclusive formation of 3p occurred in good yield when the amount of HPA was increased (entries 3-6).…”

“…The hypervalent iodine(III) reagent, PIFA, induced biaryl coupling reaction involving aromatic cation-radical intermediates was originally developed by our group 89,94,95,97) and applied to the synthesis of some useful heterocycles by Moreno et al 109) The commonly used conditions for biaryl coupling reactions using PIFA are as follows: (i) in poorly nucleophilic solvents such as TFE or HFIP; and (ii) in the presence of BF 3 ·Et 2 O (2 eq) in CH 2 Cl 2 .…”