A Short, Protecting Group-Free Total Synthesis of Bruceollines D, E, and J

Lopchuk, Justin M.; Green, Ilene L.; Badenock, Jeanese C.; Gribble, Gordon W.

doi:10.1021/ol402042f

Cited by 31 publications

(16 citation statements)

References 28 publications

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“…This yield is higher than that reported previously (51 %o verall yield). [23] In addition, compound 19 could serve as ak ey intermediate for the syntheses of bruceollines E( 20)a nd J( 21), reportedb yL opchuke tal. recently.…”

Section: Synthetic Applicationsmentioning

confidence: 99%

Facile Installation of 2‐Reverse Prenyl Functionality into Indoles by a Tandem N‐Alkylation–Aza‐Cope Rearrangement Reaction and Its Application in Synthesis

Chen

Fan

Zhang

et al. 2015

Chemistry A European J

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An unprecedented tandem N-alkylation-ionic aza-Cope (or Claisen) rearrangement-hydrolysis reaction of readily available indolyl bromides with enamines is described. Due to the complicated nature of the two processes, an operationally simple N-alkylation and subsequent microwave-irradiated ionic aza-Cope rearrangement-hydrolysis process has been uncovered. The tandem reaction serves as a powerful approach to the preparation of synthetically and biologically important, but challenging, 2-reverse quaternary-centered prenylated indoles with high efficiency. Notably, unusual nonaromatic 3-methylene-2,3-dihydro-1H-indole architectures, instead of aromatic indoles, are produced. Furthermore, the aza-Cope rearrangement reaction proceeds highly regioselectively to give the quaternary-centered reverse prenyl functionality, which often produces a mixture of two regioisomers by reported methods. The synthetic value of the resulting nonaromatic 3-methylene-2,3-dihydro-1H-indole architectures has been demonstrated as versatile building blocks in the efficient synthesis of structurally diverse 2-reverse prenylated indoles, such as indolines, indole-fused sultams and lactams, and the natural product bruceolline D.

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Section: Synthetic Applicationsmentioning

confidence: 99%

Facile Installation of 2‐Reverse Prenyl Functionality into Indoles by a Tandem N‐Alkylation–Aza‐Cope Rearrangement Reaction and Its Application in Synthesis

Chen

Fan

Zhang

et al. 2015

Chemistry A European J

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“…We then subjected 4ab to an umber of synthetic manipulations to demonstrate that various interesting indole derivatives can be accessed using this protocol (Scheme 4). Fore xample,o xidation of 4ab with SeO 2 led to cyclopenta- [b]indole-1,2-dione 7,w hich is the protected form of ac hiral analog of the natural product bruceolline E. [21] Thediketone 7 can be converted to the corresponding quinoxaline derivative 8 in nearly quantitative yield. Bromination of 4ab with NBS predominantly furnished 6-bromocyclopenta [b]indolone 9 along with as mall amount of 8-bromo derivative.T his postindolization manipulation thus overcomes the regioselectivity problem (see Table 3) encountered in the synthesis of 6substituted cyclopenta [b]indolone derivatives.T he carbonyl group of 4ab can be converted to oxime by treatment with hydroxylamine and the (E)-oxime 10 was isolated in 90 % yield with 9:1d.r.…”

Section: Forschungsartikelmentioning

confidence: 99%

Catalytic Enantioselective Desymmetrizing Fischer Indolization through Dynamic Kinetic Resolution

et al. 2021

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The first catalytic enantioselective Fischer indolization of prochiral diketones containing enantiotopic carbonyl groups is developed and shown to proceed through dynamic kinetic resolution (DKR). Catalyzedb yt he combination of as pirocyclic chiral phosphoric acid and ZnCl 2 (Lewis acid assisted Brønsted acid), this direct approach combines 2,2disubstituted cyclopentane-1,3-diones with N-protected phenylhydrazines to furnish cyclopenta[b]indole derivatives containing an all-carbon quaternary stereocenter with good to excellent enantioselectivities. Scheme 1. Catalytic enantioselective Fischer indolizations.

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“…Despite their potential in medicinal chemistry, few syntheses of these natural alkaloids have been reported to date . Bruceollines H and I differ from the others by the presence of an OH group on the indole ring.…”

Section: Cyclopenta[b]indole Alkaloidsmentioning

confidence: 99%

“…107 Despite their potential in medicinal chemistry, few syntheses of these natural alkaloids have been reported to date. [108][109][110] Bruceollines H and I differ from the others by the presence of an OH group on the indole ring. To date, their cytotoxicity has been tested in vitro against five human tumour cell lines.…”

Section: Cyclopenta[b]indole Alkaloidsmentioning

confidence: 99%

From synthetic control to natural products: a focus on N‐heterocycles

Prandi

Occhiato

2019

Pest Management Science

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Natural products containing a N‐heterocycle motif are widespread in nature and medicinal plants, in particular, have proved to be a source of almost unlimited N‐derived structures with high molecular diversity. Because of their intrinsic potential for use in both biomedical and agricultural applications, there is a general need for new compounds and for the synthesis of ‘natural‐inspired’ analogues. Importantly, transition of a natural product from discovery to a ‘market lead’ is associated with an increasingly challenging demand for more of the compound, which cannot be met by isolation from natural plant sources, often due to low extraction yields and uneven availability of the plant source itself. Synthesis remains the most reliable approach to provide valuable products for the market. In this review, a comprehensive overview of our contribution to synthetic access to N‐derived natural products is given. Major strengths of the proposed methodologies are discussed critically. © 2019 Society of Chemical Industry

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A Short, Protecting Group-Free Total Synthesis of Bruceollines D, E, and J

Cited by 31 publications

References 28 publications

Facile Installation of 2‐Reverse Prenyl Functionality into Indoles by a Tandem N‐Alkylation–Aza‐Cope Rearrangement Reaction and Its Application in Synthesis

Facile Installation of 2‐Reverse Prenyl Functionality into Indoles by a Tandem N‐Alkylation–Aza‐Cope Rearrangement Reaction and Its Application in Synthesis

Catalytic Enantioselective Desymmetrizing Fischer Indolization through Dynamic Kinetic Resolution

From synthetic control to natural products: a focus on N‐heterocycles

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