Synthesis of Functionalized Benzo[<i>b</i>]furans via Oxidative Cyclization of<i>o</i>-Cinnamyl Phenols

Rehan, Mohammad; Nallagonda, Rajender; Das, Braja Gopal; Meena, Tannu; Ghorai, Prasanta

doi:10.1021/acs.joc.6b02752

Cited by 26 publications

(12 citation statements)

References 100 publications

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“…ether. ); 1 H NMR (400 MHz, CDCl 3 ) δ=6.96‐6.90 ( m , 2H, Ar H ), 6.75‐6.69 ( m , 1H, Ar H ), 6.08‐5.96 ( m , 1H, C H =), 5.21‐5.12 ( m , 2H, =C H 2 ), 4.82 ( broad s , 1H, O H ), 3.39 ( dt , J =6.3, 1.6 Hz, 2H, C H 2 ), 2.27 ( s , 3H, C H 3 ) ppm; Data in agreement with literature …”

Section: Methodsmentioning

confidence: 99%

“…); 1 H NMR (400 MHz, CDCl 3 ) δ = 6.96-6.90 (m, 2H, ArH), 6.75-6.69 (m, 1H, ArH), 6.08-5.96 (m, 1H, CH =), 5.21-5.12 (m, 2H, = CH 2 ), 4.82 (broad s, 1H, OH), 3.39 (dt, J = 6.3, 1.6 Hz, 2H, CH 2 ), 2.27 (s, 3H, CH 3 ) ppm; Data in agreement with literature. [28] 2-Allyl-4-chlorophenol 4-(Allyloxy)-chlorobenzene (1.18 g, 7.0 mmol) used to yield a yellow oil (0.89 g, 76 % yield); R f = 0.3 (10 % EtOAc/pet. ether.…”

Section: -Allyl-4-methylphenolmentioning

confidence: 99%

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Application of Electrochemical Processes to Classical Iodocyclisation: Utility for Selectivity and Mechanistic Insight

Seavill

Wilden

2019

ChemElectroChem

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The hazards and difficulties of handling elemental halogens such as I2 can be circumvented through the electrochemical generation of these species in situ and ‘on‐demand’. Advantages of this approach include the halogen being introduced into the reaction mixture at a steady rate, ensuring low concentrations to prevent halogenation of reactive aromatic rings. We also demonstrate that the Lewis acid required to promote this reaction, a Zn(II) salt, can also be generated in situ from a zinc‐coated graphite electrode in a clean and energy‐efficient manner. Mechanistic studies indicate an unusual pathway, which provides selectivity for the iodocyclisation without the often‐problematic electrophilic aromatic iodination of the aryl ring.

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Section: Methodsmentioning

confidence: 99%

Section: -Allyl-4-methylphenolmentioning

confidence: 99%

Application of Electrochemical Processes to Classical Iodocyclisation: Utility for Selectivity and Mechanistic Insight

Seavill

Wilden

2019

ChemElectroChem

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“…From the natural product honokiol, which contains a o-allylphenol fragment, a benzofuran scaffold was produced through a Wacker-type intramolecular cyclization, using PdCl 2 , NaOAc, and O 2 , in DMA/H 2 O [73]. Different substituted o-allylphenol derivatives, prepared via a Friedel−Crafts alkylation of cinnamyl alcohol with phenols, using Re 2 O 7 catalyst in acetonitrile as solvent, underwent oxidative cyclization, using PdCl 2 (C 2 H 4 ) 2 as catalyst and BQ as oxidant [74]. A simple sequential reaction protocol has been developed for the synthesis of functionalized 2-benzyl benzofurans via Friedel−Crafts alkylation of phenols with cinnamyl alcohols in the presence of Re 2 O 7 catalyst, followed by Pd(II)-catalyzed oxidative annulation of in situ generated o-cinnamyl phenols.…”

Section: From O-allylphenolsmentioning

confidence: 99%

Last Decade of Unconventional Methodologies for the Synthesis of Substituted Benzofurans

Chiummiento¹,

D’Orsi²,

Funicello³

et al. 2020

Molecules

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This review describes the progress of the last decade on the synthesis of substituted benzofurans, which are useful scaffolds for the synthesis of numerous natural products and pharmaceuticals. In particular, new intramolecular and intermolecular C–C and/or C–O bond-forming processes, with transition-metal catalysis or metal-free are summarized. (1) Introduction. (2) Ring generation via intramolecular cyclization. (2.1) C7a–O bond formation: (route a). (2.2) O–C2 bond formation: (route b). (2.3) C2–C3 bond formation: (route c). (2.4) C3–C3a bond formation: (route d). (3) Ring generation via intermolecular cyclization. (3.1) C7a-O and C3–C3a bond formation (route a + d). (3.2) O–C2 and C2–C3 bond formation: (route b + c). (3.3) O–C2 and C3–C3a bond formation: (route b + d). (4) Benzannulation. (5) Conclusion.

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“…Similarly, o-cinnamyl phenols, on oxidative cyclisation, results in 2-benzyl benzofurans [20], while o-alkylphenols, on annulative reaction, gives 3-aminobenzofurans [21] (Figure 8).…”

Section: 3-substituted Benzofuranmentioning

confidence: 99%

The Oxygen-Containing Fused Heterocyclic Compounds

Venkatachalam¹,

N²

2020

Heterocycles - Synthesis and Biological Activities

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The oxygen-containing heterocycles are an important class of compounds in organic chemistry. These compounds are used as drugs (coumarin and oxazole), solvent (tetrahydrofuran), flavors, and fragrances (lactones). The fusion of aromatic ring to the oxygen-heterocycle will change the electron density; thereby, the physical/chemical/biological properties will alter. Also, the preparation of these fused molecules will require a different strategy/method/reaction condition. The topics covered in this chapter are the general synthetic methods and uses of fused heterocyclic compounds containing oxygen as a heteroatom. The derivatization of the primary scaffold is excluded from this chapter. Some of the fused compounds are coumarin (benzopyrans) and piclozotan (benzoxazepines).

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Synthesis of Functionalized Benzo[b]furans via Oxidative Cyclization ofo-Cinnamyl Phenols

Cited by 26 publications

References 100 publications

Application of Electrochemical Processes to Classical Iodocyclisation: Utility for Selectivity and Mechanistic Insight

Application of Electrochemical Processes to Classical Iodocyclisation: Utility for Selectivity and Mechanistic Insight

Last Decade of Unconventional Methodologies for the Synthesis of Substituted Benzofurans

The Oxygen-Containing Fused Heterocyclic Compounds

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