Total Synthesis of Highly Oxygenated Bisabolane Sesquiterpene Isolated from <i>Ligularia lankongensis</i>: Relative and Absolute Configurations of the Natural Product

Kobayashi, Kenichi; Kunimura, Risako; Takagi, Hirokazu; Hirai, Misaki; Kogen, Hiroshi; Harada, Hiroshi; Kuroda, Chiaki

doi:10.1021/acs.joc.7b02688

Cited by 13 publications

(7 citation statements)

References 25 publications

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“…Nevertheless, these unselective reactions were used in efforts to establish the configurations of natural products. The diastereomers of the addition products 867 485 and 869 486 were separated and individually converted to advanced intermediates that could be compared spectroscopically to natural products.…”

Section: Additions To Other Acyclic Carbonyl Compoundsmentioning

confidence: 99%

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

et al. 2020

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This review describes the additions of allylmagnesium reagents to carbonyl compounds and to imines, focusing on the differences in reactivity between allylmagnesium halides and other Grignard reagents. In many cases, allylmagnesium reagents either react with low stereoselectivity when other Grignard reagents react with high selectivity, or allylmagnesium reagents react with the opposite stereoselectivity. This review collects hundreds of examples, discusses the origins of stereoselectivities or the lack of stereoselectivity, and evaluates why selectivity may not occur and when it will likely occur. CONTENTS 4.2.5. Additions to β-Substituted Aldehydes 4.2.6. Additions to Aldehydes with Distant Chelating Groups 4.3. Additions to Cyclic Ketones 4.3.1. Alkoxy-Substituted Cyclic Ketones 4.3.2. Additions to Alkoxy-Substituted Five-Membered-Ring Ketones 4.3.3. Additions to Alkoxy-Substituted Four-Membered-Ring Ketones 4.4. Additions of Allylmagnesium Halides to Cyclic Hemiacetals 5. Diastereoselectivity of Reactions of Allylmagnesium Reagents with Carbonyl Compounds by Felkin−Anh Control 5.1. Felkin−Anh Stereoselectivity 5.2. Additions to α-Chiral Acyclic Ketones 5.3. Additions to Chiral Exocyclic Ketones and Aldehydes 5.4. Additions of Allylmagnesium Halides to Chiral Cyclic Ketones Controlled by Felkin−Anh Selectivity 5.5. Additions of Allylmagnesium Halides to Chiral Acyclic Aldehydes 6. Diastereoselectivity of Reactions with Carbonyl Compounds by Steric Approach Control 6.1. Steric Approach Control and Stereoselectivity

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Section: Additions To Other Acyclic Carbonyl Compoundsmentioning

confidence: 99%

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

et al. 2020

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“…30 Kuroda et al recently established the absolute configurations at C-8 and C-10 in a side chain of some bisabolane compounds by total synthesis. 31,32 However, the absolute configuration at the C-8 position and the epoxide at C-10/C-11 in compounds 1 to 8 could not be determined using the spectroscopic methods because the requisite NMR data were not feasible to obtain as part of this study.…”

Section: The Roots Of 3 Samples Collected In Yunnan and Sichuanmentioning

confidence: 98%

Bisabolane, Oplopane, and Lignan Constituents of Cremanthodium campanulatum Collected in China

Saito

Ichihara

Takiguchi

et al. 2019

Natural Product Communications

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The chemical constituents in the roots of 3 Cremanthodium campanulatum Diels (Asteraceae) samples collected in Yunnan and Sichuan Provinces, China, were chemically investigated. A total of 8 bisabolane-type sesquiterpenoids, 2 of which were new, and a new oplopane-type sesquiterpenoid, along with a new lignan were isolated and their structures elucidated based on spectroscopic analyses. This is the first report on the chemical study of C. campanulatum.

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“…42 Kuroda et al recently established the absolute configurations at C-8 and C-10 in a side chain of some bisabolane compounds by total synthesis. 43,44…”

Section: On the Structures Of Bisabolanesmentioning

confidence: 99%

Chemical Studies of Cremanthodium (Asteraceae) Species; Sesquiterpenoids and Related Compounds

Tori

Saito

Gong

et al. 2019

Natural Product Communications

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Chemical constituents of Cremanthodium angustifolium, C. brunneopilosum, C. campanulatum, C. daochengense, C. discoideum, C. ellisii, C. helianthus, C. lineare, C. nobile, C. potaninii, C. principis, C. pulchrum, C. rhodocephalum, C. stenactinium, C. pleurocaule, and C. stenoglossum were reviewed. They produced mainly sesquiterpenoids–bicyclic and/or tricyclic eremophilanes, bisabolanes, bakkanes–and related compounds. Cremanthodium was shown to be close to Ligularia in chemical constituents.

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Total Synthesis of Highly Oxygenated Bisabolane Sesquiterpene Isolated from Ligularia lankongensis: Relative and Absolute Configurations of the Natural Product

Cited by 13 publications

References 25 publications

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

Bisabolane, Oplopane, and Lignan Constituents of Cremanthodium campanulatum Collected in China

Chemical Studies of Cremanthodium (Asteraceae) Species; Sesquiterpenoids and Related Compounds

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