Synthesis and Structure Revision of Goupiolone A: A Benzotropolone Natural Product

Fukui, Nobuaki; Ohmori, Ken; Suzuki, Keisuke

doi:10.1002/hlca.201200439

Cited by 12 publications

(16 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spectroscopic data of synthesized 1 were in full agreement with those of natural 1. [1,2] In addition, the 1 H and 13 C NMR data of synthesized 5 were completely consistent with those of the natural goupiolone B, except for the 13 C NMR chemical shift of C-2' (∆δ C = 5.7 ppm) ( Table 1). [1] The previously reported value of C-2' is presumably a typographical error.…”

supporting

confidence: 64%

“…[1] Since 1 and 2 behave as genotoxins that are stronger than the antineoplastic agent doxorubicin, they are candidates for anticancer drugs. [1] Goupiolone A (1) is a benzotropolone derivative [1,2] and presumed to be produced from catechol (3) and ethyl gallate (4) by oxidative coupling via a benzobicyclo[3.2.1]octane-type intermediate (Scheme 1). Other benzotropolone derivatives from natural sources, such as purpurogallin glycosides, [3] theaflavins, [4] fomentariol, [5] aurantricholone, [6] and crocipodin, [7] are also produced by the coupling between catechol and pyrogallol derivatives.…”

mentioning

confidence: 99%

“…Firstly, we synthesized goupiolone A (1). Thus far, there have been two reports for the total synthesis of 1; however, these methods required many steps [19 steps (2012), [2] 9 steps (2017) [12] ]. In this study, the non-enzymatic biomimetic method developed for theaflavins, black tea pigments with a benzotropolone moiety, [13] was applied to the synthesis of 1.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Structural Revision and Biomimetic Synthesis of Goupiolone B

et al. 2017

View full text Add to dashboard Cite

Goupiolones A and B are unique phenolic compounds with significant DNA-damaging activity. In this study, the structure of goupiolone B was revised on the basis of DFT calculations of the 13 C NMR chemical shifts and biosynthetic considerations. The dibenzobicyclo[3.2.2]nonane skeleton of the revised structure suggested that goupiolone B was produced by oxidative coupling between catechol and goupiolone A, which was strongly supported by this biomimetic synthesis. Furthermore, the racemization of goupiolone B was observed during the examination for the chiral separation of its racemic mixture. A plausible racemization mechanism involving α-ketol rearrangement was also proposed.

show abstract

supporting

confidence: 64%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Structural Revision and Biomimetic Synthesis of Goupiolone B

et al. 2017

View full text Add to dashboard Cite

show abstract

“…[26] Scheme5.Exemplary C,C-couplings with the 9-brominatedp recursor 28 of 9-C-functionalized benzotropolones. The ester moiety survived the ensuingc leavage of the methoxy groups with BBr 3 ,too.…”

mentioning

confidence: 99%

Regioselective Bromination of Benzocycloheptadienones for the Synthesis of Substituted 3,4‐Benzotropolones Including Goupiolone A

Arican

Braukmüller

Brückner

2017

Chemistry A European J

View full text Add to dashboard Cite

Type-18 or -23 benzocycloheptadienones are readily prepared by ring-closing olefin metatheses. Adding Br to 23 and eliminating HBr gave the bromoolefin 28 using DBU or its isomer iso-28 using DABCO, both with near-perfect regiocontrol. Both 28 and iso-28 underwent Sonogashira, Suzuki, Negishi, and Heck couplings as well as Pd-catalyzed alkoxycarbonylations. Hydrolysis of the resulting α-ketoketals and enolization of the liberated α-diketones delivered a portfolio of hitherto unknown 3,4-benzotropolones. The 8-ethoxycarbonylated dimethyl-3,4-benzotropolone 50 obtained by this route was dimethylated to give goupiolone A (52). This synthesis encompasses 9 steps from 22, that is, half as many as the only previous synthesis (19 steps). A variant of our route afforded the 1,8-dibromide 54. Coupling with excess phenylboronic acid and ketal hydrolysis provided the diphenylated benzotropolone 56 and suggests a strategy, by which the natural bispulvinone aurantricholone (7) might be reached.

show abstract

“…198–199 The cyclopropyl benzocyclobutene precursor 54-1 was prepared following protocols developed previously. 198 The key ring expansion step was operated under thermal conditions to give a mixture of two diastereoisomers 54-3 .…”

Section: Synthesis Of Naturally Occurring Tropones and Tropolonesmentioning

confidence: 99%

Synthesis of naturally occurring tropones and tropolones

et al. 2014

View full text Add to dashboard Cite

Tropones and tropolones are an important class of seven-membered non-benzenoid aromatic compounds. They can be prepared directly by oxidation of seven-membered rings. They can also be derived from cyclization or cycloaddition of appropriate precursors followed by elimination or rearrangement. This review discusses the types of naturally occurring tropones and tropolones and outlines important methods developed for the synthesis of tropone and tropolone natural products.

show abstract

Synthesis and Structure Revision of Goupiolone A: A Benzotropolone Natural Product

Cited by 12 publications

References 43 publications

Structural Revision and Biomimetic Synthesis of Goupiolone B

Structural Revision and Biomimetic Synthesis of Goupiolone B

Regioselective Bromination of Benzocycloheptadienones for the Synthesis of Substituted 3,4‐Benzotropolones Including Goupiolone A

Synthesis of naturally occurring tropones and tropolones

Contact Info

Product

Resources

About