Prenylated Flavones from <i>Artocarpus Lanceifolius</i> and their Cytotoxic Properties against P-388 Cells

Musthapa, Iqbal; Latip, Jalifah; Takayama, Hiromitsu; Juliawaty, Lia Dewi; Hakim, Euis H.; Syah, Yana Maolana

doi:10.1177/1934578x0900400710

Cited by 10 publications

(13 citation statements)

References 9 publications

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“…7 For clarity, the mechanism for formation of one enantiomer of the major diastereomer is shown in Figure 3 (See SI for detailed reaction profiles for formation of the other diastereomer and its enantiomer are reported). First, addition of the chiral catalyst results in a tetrahedral intermediate (11) with N2 poised to leave. The barrier to extrude nitrogen is low and this process is predicted to be highly exergonic, forming one major rotamer of Rh carbene (8).…”

Section: Alkyl/alkyl Stereogenic Insertion Centersmentioning

confidence: 99%

“…This facile method to generate trisubstituted benzodihydrofuran cores enables the asymmetric synthesis of multiple classes of natural products, patented biologically active small molecules, and their analogs, to be rapidly synthesized (Figure 1). [11][12][13][14][15][16][17] Previous work by Taber 18 and Doyle 19 used chiral C-H insertion centers and acceptor-substituted carbenes to create selectivity models for their respective systems. Taber demonstrated that the stereochemistry of the C-H insertion site was retained and attributed this observation to a concerted mechanism (Figure 2A).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Divergent Stereochemical Outcomes in the Insertion of Donor/Donor Carbenes into the C–H Bonds of Stereogenic Centers

Dishman

Laconsay

Fettinger

et al. 2021

Preprint

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Intramolecular C-H insertions with donor/donor dirhodium carbenes provide a concise and highly stereoselective method to set two contiguous stereocenters in a single step. Herein, we report the insertion of donor/donor carbenes into stereogenic carbon centers allowing access to trisubstituted benzodihydrofurans in a single step. This study illuminates, for the first time, the stereochemical impact on the carbene center and delineates the structural factors that enable control over both stereogenic centers. Sterically bulky, highly activated C-H insertion centers exhibit high substrate control yielding a single diastereomer and a single enantiomer of product regardless of the catalyst used. Less bulky, less activated C-H insertion centers exhibit catalyst control over the diastereomeric ratio (dr), where a single enantiomer of each diastereomer is observed with high selectivity. A combination of experimental studies and DFT calculations elucidate the origin of these results. First, hydride transfer from the stereogenic insertion site proceeds with high stereoselectivity to the carbene center, thus determining the absolute configuration of the product. Second, the short lived zwitterionic intermediate can diastereoselectively ring-close by a hitherto unreported SE2 mechanism that is either controlled by the substrate or the catalyst. These results demonstrate that donor/donor carbenes undergo uniquely stereoselective reactions that originate from a stepwise reaction mechanism, in contrast to the analogous concerted reactions of carbenes with one or more electron-withdrawing groups attached.

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Section: Alkyl/alkyl Stereogenic Insertion Centersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Divergent Stereochemical Outcomes in the Insertion of Donor/Donor Carbenes into the C–H Bonds of Stereogenic Centers

Dishman

Laconsay

Fettinger

et al. 2021

Preprint

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Section: Table 1 Alkyl/aryl Stereogenic Insertion Centersmentioning

confidence: 99%

“…Facile access to benzodihydrofuran cores enables multiple classes of asymmetric natural products, patented biologically active small molecules, and their respective analogs to be rapidly synthesized (Figure 1). [11][12][13][14][15][16][17] Previous work by Taber 18 and Doyle 19 used chiral C-H insertion centers and acceptor-substituted carbenes to create selectivity models for their respective systems. Taber demonstrated that the stereochemistry of the C-H insertion site was retained and attributed this observation to a concerted mechanism (Figure 2A).…”

Section: Introductionmentioning

confidence: 99%

Divergent Stereochemical Outcomes in the Insertion of Donor/Donor Carbenes into the C–H Bonds of Stereogenic Centers

Shaw

Dishman

Laconsay

et al. 2021

Preprint

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Intramolecular C-H insertions with donor/donor dirhodium carbenes provide a concise and highly stereoselective method to set two contiguous stereocenters in a single step. Herein, we report the insertion of donor/donor carbenes into stereogenic carbon centers allowing access to trisubstituted benzodihydrofurans in a single step. This study illuminates, for the first time, the stereochemical impact on the carbene center and delineates the structural factors that enable control over both stereogenic centers. Sterically bulky, highly activated C-H insertion centers exhibit high substrate control yielding a single diastereomer and a single enantiomer of product regardless of the catalyst used. Less bulky, less activated C-H insertion centers exhibit catalyst control over the diastereomeric ratio (dr) wherein a single enantiomer of each diastereomer is observed. A combination of experimental studies and DFT calculations elucidates the origin of these results. First, hydride transfer from the stereogenic insertion site proceeds with high stereoselectivity to the carbene center, thus determining the absolute configuration of the product. Second, the short lived zwitterionic intermediate can undergo diastereoselective ring-closure by an SE2 mechanism that is either controlled by the substrate or the catalyst. These results demonstrate that donor/donor carbenes exhibit uniquely stereoselective reactions that originate from a stepwise reaction mechanism, in contrast to the analogous concerted reactions of carbenes with one or more electron-withdrawing groups attached. ASSOCIATED CONTENT Supporting InformationThe Supporting Information is available free of charge on the ACS Publications website. Experimental details, characterization data, and spectra (PDF)Computational data and procedures.

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Tyrosinase Inhibitory Properties of Compounds Isolated from Artocarpus integer Roots

Siridechakorn,

Shinta,

Ardiansah

et al. 2024

J. Nat. Prod.

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Prenylated Flavones from Artocarpus Lanceifolius and their Cytotoxic Properties against P-388 Cells

Cited by 10 publications

References 9 publications

Divergent Stereochemical Outcomes in the Insertion of Donor/Donor Carbenes into the C–H Bonds of Stereogenic Centers

Divergent Stereochemical Outcomes in the Insertion of Donor/Donor Carbenes into the C–H Bonds of Stereogenic Centers

Divergent Stereochemical Outcomes in the Insertion of Donor/Donor Carbenes into the C–H Bonds of Stereogenic Centers

Tyrosinase Inhibitory Properties of Compounds Isolated from Artocarpus integer Roots

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