An efficient synthesis of 4-alkenyl/alkynyl-6-methyl-2-pyrones via Pd-catalysed coupling on 4-bromo-6-methyl-2-pyrone

Marrison, Lester R.; Dickinson, Julia M.; Ahmed, R. Nasir; Fairlamb, Ian J. S.

doi:10.1016/s0040-4039(02)02207-4

Cited by 54 publications

(41 citation statements)

References 14 publications

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“…On initial inspection of Table 2, it is clear that 1 is able to efficiently mediate the cross-coupling of 2h with organoboronic acids 3a-f. In all cases, with the exception of 3e, higher yields and more purer products (>90%; in selected examples >95%, pure by inspection of the 1 H NMR spectra of the crude products) are obtained compared to those previously reported, using Pd(OAc) 2 as the catalyst [45]. For example, 3a reacted with 2h to give 4w in 86% yield after 6 h, which compares to 56% under our previous best conditions (entry 1, Table 2).…”

Section: Suzuki-miyaura Coupling Of a Brominated 2-pyronesmentioning

confidence: 82%

“…Lowering catalyst loadings also reduces the amount of trace quantities of palladium present in the final products. In recent work, we have applied Suzuki-Miyaura methodology to the synthesis of novel chemotherapeutic agents based on the 2-pyrone-ring system [45][46][47][48]. The electrophilic partner is 4-bromo-6-methyl-2-pyrone 2h, which we have established is a relatively activated substrate.…”

Section: Suzuki-miyaura Coupling Of a Brominated 2-pyronesmentioning

confidence: 99%

“…The following compounds characterized by 1 H, 13 C NMR spectroscopy and mass spectrometry are known within the literature: biphenyl 4a [52], 4-methylbiphenyl 4b [45], 4 -formylbiphenyl 4c [53], 4-chlorobiphenyl 4d [46] 4-acetylbiphenyl 4e [54], 4-acetyl-4 -methylbiphenyl 4f [55], 4-acetyl-4 -formylbiphenyl 4g [56], 4-acetyl-4 -chlorobiphenyl 4h [57], 4-nitrobiphenyl 4i [58], 4-nitro-4 -methylbiphenyl 4j [59], 4 -nitro-biphenyl-4-carbaldehyde 4k [60], 4-nitro-4 -chlorobiphenyl 4l [61], 2-methoxybiphenyl 4m [62], 3-(2-methoxyphenyl)thiophene 4n [63], 2-methoxy-trans-stilbene 4o [64], 2-methoxycarbonylbiphenyl 4p [65], 3-(2-methoxycarbonylphenyl)thiophene 4q [66], 2-methoxycarbonyl-trans-stilbene 4r [67], 2,6-dimethylbiphenyl 4s [68], 2,6-dimethyl-4 -methylbiphenyl 4t [42], 2,6-dimethyl-4 -formylbiphenyl 4u [42], 2,6-dimethyl-4 -chlorobiphenyl 4v [69], 4-bromo-6-methyl-2-pyrone 2h [48], 4-phenyl-6-methyl-2-pyrone 4w, 4-(4 -methylphenyl)-6-methyl-2-pyrone 4x [48], 4-(4 -formylphenyl)-6-methyl-2-pyrone 4y [48], 4-(4 -chlorophenyl)-6-methyl-2-pyrone 4z [48], 4-(2 -phenyl-trans-ethenyl)-6-methyl-2-pyrone 4ab [48]. …”

Section: Typical Suzuki Reactionmentioning

confidence: 99%

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Bis(triphenylphosphine)palladium(II)phthalimide – an easily prepared precatalyst for efficient Suzuki–Miyaura coupling of aryl bromides

Chaignon

Fairlamb

Kapdi

et al. 2004

Journal of Molecular Catalysis A: Chemical

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Section: Suzuki-miyaura Coupling Of a Brominated 2-pyronesmentioning

confidence: 82%

Section: Suzuki-miyaura Coupling Of a Brominated 2-pyronesmentioning

confidence: 99%

Section: Typical Suzuki Reactionmentioning

confidence: 99%

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Bis(triphenylphosphine)palladium(II)phthalimide – an easily prepared precatalyst for efficient Suzuki–Miyaura coupling of aryl bromides

Chaignon

Fairlamb

Kapdi

et al. 2004

Journal of Molecular Catalysis A: Chemical

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“…As summarized in Schemes 2, 2-and 4-substituted arylzinc halides which were prepared using highly active zinc 5 were coupled with 4-bromo-6-methyl-2-pyrone in the presence of a catalytic amount of Pd(PPh 3 ) 4 . The coupling reactions proceeded smoothly under the reaction conditions shown below and resulted in the coupling products 1a and 1b (Scheme 2) in good to excellent yields.…”

Section: Scheme 1 Synthetic Pathways For the Preparation Of 4-substitmentioning

confidence: 99%

“…To accomplish this goal, the coupling reaction of I with aryl acid chlorides was carried out first. 4 ]. The coupling product 2a was achieved in excellent isolated yield (94%, entry 1, Table 1).…”

Section: Scheme 1 Synthetic Pathways For the Preparation Of 4-substitmentioning

confidence: 99%

A Facile Synthetic Route for the Preparation of 4-Substituted 6-Methyl-2-pyrone Derivatives via Organozinc Reagents

Rieke¹,

Kim²

2011

Synlett

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A novel synthetic pathway for the preparation of 4-substituted 2-pyrone derivatives has been developed. It consists of two different methods; the first represents the Negishi coupling reaction utilizing easily accessible organozinc reagents. More significantly, the other is a new method utilizing a new organozinc reagent, 4-pyronylzinc bromide, which is easily prepared by highly active zinc under mild conditions. In our continuing study on the development of organozinc reagents, we have found a new synthetic method for the preparation of biologically interesting materials, 2-pyrone derivatives.Due to the particular interest in the 2-pyrone moiety in natural products, 1 studies have focused on the development of a versatile synthetic methodology for the preparation of 2-pyrone derivatives. Among the known procedures, construction of pyrone ring system from acyclic precursors 2 and introduction of substituents onto the preformed pyrone ring are the predominant approaches. 3 While these routes provided a variety of 2-pyrone derivatives, major drawbacks to these pathways are multistep synthesis and ring opening. Thus, in spite of the present methodologies, there is still a need to explore a versatile synthetic methodology for the preparation of 2-pyrone derivatives.We herein would like to report our results of a convenient synthetic route for the preparation of 2-pyrone derivatives. Interestingly, route B in this study leads to a unique way of introducing more versatile functional groups on the 4-position in 2-pyrones.Prior to the general investigation on the preparation of 2-pyrone derivatives, we have performed the reactions with 4-bromo-6-methyl-2-pyrone 4 because this moiety is found in a large number of biologically active materials and also the precursor, 4-hydroxy-6-methyl-2-pyrone, was readily available.In order to accomplish the goals of this study, we designed two different approaches, depicted in Scheme 1. First, the well-known Negishi cross-coupling reaction was carried out using 4-bromo-6-methyl-2-pyrone and easily accessible organozinc reagents (route A in Scheme 1). And, the second approach is to make a new organozinc reagent and utilize it in many subsequent coupling reactions (route B in Scheme 1). Scheme 1 Synthetic pathways for the preparation of 4-substituted 2-pyronesSince similar approaches with route A have been executed using organotin and organoborane compounds, 3 we carried out only two representative reactions to verify the utility of organozinc reagent and 4-bromo-6-methyl-2-pyrone. As summarized in Schemes 2, 2-and 4-substituted arylzinc halides which were prepared using highly active zinc 5 were coupled with 4-bromo-6-methyl-2-pyrone in the presence of a catalytic amount of Pd(PPh 3 ) 4 . The coupling reactions proceeded smoothly under the reaction conditions shown below and resulted in the coupling products 1a and 1b (Scheme 2) in good to excellent yields. Mild reaction conditions (2-4 h at r.t.) were required to complete the coupling reaction in THF.Even though this procedure was satis...

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Polyfunctional Tin Organometallics for Organic Synthesis

Fouquet¹,

Herve²

2005

Handbook of Functionalized Organometallics

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An efficient synthesis of 4-alkenyl/alkynyl-6-methyl-2-pyrones via Pd-catalysed coupling on 4-bromo-6-methyl-2-pyrone

Cited by 54 publications

References 14 publications

Bis(triphenylphosphine)palladium(II)phthalimide – an easily prepared precatalyst for efficient Suzuki–Miyaura coupling of aryl bromides

Bis(triphenylphosphine)palladium(II)phthalimide – an easily prepared precatalyst for efficient Suzuki–Miyaura coupling of aryl bromides

A Facile Synthetic Route for the Preparation of 4-Substituted 6-Methyl-2-pyrone Derivatives via Organozinc Reagents

Polyfunctional Tin Organometallics for Organic Synthesis

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