Enantioselective total synthesis of (+)-labd-8(17)-ene-3β,15-diol and (−)-labd-8(17)-ene-3β,7α,15-triol

Pemp, Alexander; Seifert, Karlheinz

doi:10.1016/s0040-4039(97)00346-8

Cited by 16 publications

(4 citation statements)

References 21 publications

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“…The discovery of the intramolecular aldol cyclizations of triketones was a milestone in asymmetric catalysis, the full impact of which would not be known for some 30 years. ,− Reported independently by the group of Hajos and Parrish and the team of Eder, Sauer, and Weichert, , the reaction involved use of catalytic amounts of ( S )-proline − to form enantioenriched enediones, which have been used in the synthesis of natural products. − These early works initiated the explosive growth in the area of organocatalysis. Although the application of enantioselective organocatalysts in synthesis is likely more environmently friendly than metal-based catalysts, few examples have been reported extending these catalysts to solvent-free reaction conditions.…”

Section: 15 Asymmetric Organocatalytic Reactionsmentioning

confidence: 99%

A Green Chemistry Approach to Asymmetric Catalysis: Solvent-Free and Highly Concentrated Reactions

2007

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In 1999, he moved to his current position at the University of Pennsylvania where he was promoted to associate professor in 2002 and professor in 2005. Walsh has received several awards, most recent of which was the 2006 Philadelphia Section Award of the ACS. Walsh's interests are in asymmetric reactions, development of new methods, reaction mechanisms, and inorganic chemistry. Hongmei Li received her B.Sc. in chemistry at the Dalian University of Technology in 1999 and her M.Sc. degree in inorganic chemistry (2002) at the Peking University with Professor Jianhua Lin. She began her Ph.D. at the University of Pennsylvania under the direction of Professor Patrick J. Walsh in 2002, during which she worked on the catalytic asymmetric addition of organozinc reagents to ketones and application of bimetallic intermediates in organic synthesis.

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Section: 15 Asymmetric Organocatalytic Reactionsmentioning

confidence: 99%

A Green Chemistry Approach to Asymmetric Catalysis: Solvent-Free and Highly Concentrated Reactions

2007

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“…We have previously used a number of commercially available modified CDs, in particular 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), and have shown in general that the binding constants of modified CDs compared to the parent CD are significantly larger. ,− However, such commercial CDs are mixtures with different substitution numbers and patterns, making correlation between substitution and host properties open to criticism. In this work we have synthesized pure known substituted CDs 2 and 4 based on literature methods − and developed innovative methods to reach the new CD hosts 5 and 6 (Table ) in order to determine accurate correlations between the binding constants and the modified CD host structures (CD 3 was commercially available).…”

Section: Introductionmentioning

confidence: 99%

Structure–Binding Effects: Comparative Binding of 2-Anilino-6-naphthalenesulfonate by a Series of Alkyl- and Hydroxyalkyl-Substituted β-Cyclodextrins

et al. 2015

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Cyclodextrins (CDs) are the most widely used organic hosts for the inclusion of guest molecules. CDs can be readily modified through substitutions of the hydroxyl groups, and these modified CDs can have different host binding properties compared to those of parent CDs. However, only relatively few systematic studies of the effects of chemical substitution on CD binding ability have been reported thus far. In this paper, we report the study of the binding properties of five different analytically pure modified β-cyclodextrin (β-CD) hosts (substituted with alkyl and/or hydroxyalkyl groups) with 2-anilino-6-naphthalenesulfonate (2,6-ANS) as guest. Binding constants for the formation of the inclusion complex between 2,6-ANS and each CD were determined using both fluorescence spectroscopy and capillary electrophoresis. Addition of modified CDs to an aqueous solution of 2,6-ANS resulted in significant enhancement of the fluorescence intensity of 2,6-ANS, as well as a significant spectral blue shift, indicative of inclusion. Inclusion of 2,6-ANS within the CD cavity was confirmed by NMR spectroscopy. Substitution at position 3 decreased the magnitude of the binding constants, while alkyl or hydroxylalkyl substitution of the primary hydroxyl at position 6 increased the magnitude of the binding constant in all cases, in relation with increasing length of the alkyl chain linker. In addition, binding constants decreased with solvent polarity when increasing amounts of methanol were added. Structure-binding correlations for CDs based on these binding constant results are presented and discussed.

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“…The 3,4-seco-podocarpane trinorditerpenoids moluccanic acid methyl ester (37) was isolated from plant extracts of Aleurites moluccana and displays moderate cytotoxic activity against the HepG2 cell line with a half maximal inhibitory concentration (IC 50 ) value of 32 µM, which was synthesized by Maier et al (Scheme 3) 28 in racemic form. Starting from known decalone 31, 29 introduction of a formyl group at C-8 followed by Robinson annulation provided tricyclic enone 32. Treatment with excess amount of Copper(II) bromide promoted the aromatization of the enone 32 in high yield, which was followed [8][9][10][11][12][13][14][15][16][17][18][19] by deprotection and Dess-Martin periodinane (DMP) oxidation to furnish ketone 35.…”

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confidence: 99%

“…Thioacetalization of Wieland-Miescher ketone (1) proceeded without deconjugation of the double bond to give thioacetal 25, which was subjected to Fischer indole synthesis leading to indole 26. Attempts to furnish (±)-aristomakine (30) from acetate (29) were not fruitful.…”

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confidence: 99%

Aspects in the Total Syntheses of Higher Terpenoids Starting From Wieland–Miescher Ketone and Its Derivative: A Review

Hagiwara

2020

Natural Product Communications

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Enantioselective total synthesis of (+)-labd-8(17)-ene-3β,15-diol and (−)-labd-8(17)-ene-3β,7α,15-triol

Cited by 16 publications

References 21 publications

A Green Chemistry Approach to Asymmetric Catalysis: Solvent-Free and Highly Concentrated Reactions

A Green Chemistry Approach to Asymmetric Catalysis: Solvent-Free and Highly Concentrated Reactions

Structure–Binding Effects: Comparative Binding of 2-Anilino-6-naphthalenesulfonate by a Series of Alkyl- and Hydroxyalkyl-Substituted β-Cyclodextrins

Aspects in the Total Syntheses of Higher Terpenoids Starting From Wieland–Miescher Ketone and Its Derivative: A Review

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