A short route to furanosesquiterpenes using a new siloxyfuran building block. The synthesis of freelingnite and dehydrolasiosperman

Jefford, Charles W.; Sledeski, Adam W.; Rossier, Jean-Claude; Boukouvalas, John

doi:10.1016/s0040-4039(00)97946-2

Cited by 57 publications

(15 citation statements)

References 30 publications

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“…Several of the components were identified by isolation (10% ethyl acetate, 90% hexane, normal phase column chromatography using silica gel) and comparison of respective 13 C NMR spectra to published values, using a 500 MHz Bruker Avance (Germany) spectrometer in d-chloroform. These were: anymol [58], t-muurolol [59], freelingnite [60], ngaione [13], epingaione and dehydrongaione and dehydroepingaione [15], myoporone and dehydromyoporone [18], myodesmone and isomyodesmone [61], myomontanone [62], eremoacetal [63], methoxymyodesert-3ene [12], 1S-acetoxymyodesert-3-ene [16], myodesert-1-ene [3], mitchellenes G and B [4], 9-hydroxydendrolasin (listed as 6-hydroxydendrolasin in literature) [46], oppositifolic acid (as 5-acetoxymethyltetradeca-trans-2,trans-4,trans-6-trienoic acid) [48], germacrene-D-4-ol (listed as 1,6-germacradien-5-ol) [64], eremophilone and santalcamphor and 9-hydroxy-7(11),9-eremophiladien-8-one [7]. These components (Figure 9) were authenticated by matching 1 H or 13 C NMR spectra to published values (citations given in brackets).…”

Section: Chromatography Methods and Compound Identification (Gc-ms And Nmr Analysis)mentioning

confidence: 99%

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

Sadgrove

Padilla-González

Green

et al. 2021

Plants

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Australia’s endemic desert shrubs are commonly aromatic, with chemically diverse terpenes and phenylpropanoids in their headspace profiles. Species from the genus Eremophila (Scrophulariaceae ex. Myoporaceae) are the most common, with 215 recognised taxa and many more that have not yet been described, widely spread across the arid parts of the Australian continent. Over the years, our research team has collected multiple specimens as part of a survey to investigate the chemical diversity of the genus and create leads for further scientific enquiry. In the current study, the diversity of volatile compounds is studied using hydrodistilled essential oils and leaf solvent extracts from 30 taxa. Several rare terpenes and iridoids were detected in chemical profiles widely across the genus, and three previously undescribed sesquiterpenes were isolated and are assigned by 2D NMR—E-11(12)-dehydroisodendrolasin, Z-11-hydroxyisodendrolasin and 10-hydroxydihydro-α-humulene acetate. Multiple sampling from Eremophila longifolia, Eremophila arbuscular, Eremophila latrobei, Eremophila deserti, Eremophila sturtii, Eremophila oppositifolia and Eremophila alternifolia coneys that species in Eremophila are highly chemovariable. However, taxa are generally grouped according to the expression of (1) furanosesquiterpenes, (2) iridoids or oxides, (3) mixtures of 1 and 2, (4) phenylpropanoids, (5) non-furanoid terpenes, (6) mixtures of 4 and 5, and less commonly (7) mixtures of 1 and 5. Furthermore, GC–MS analysis of solvent-extracted leaves taken from cultivated specimens conveys that many heavier ‘volatiles’ with lower vapour pressure are not detected in hydrodistilled essential oils and have therefore been neglected in past chemical studies. Hence, our data reiterate that chemical studies of the genus Eremophila will continue to describe new metabolites and that taxon determination has limited predictive value for the chemical composition.

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Section: Chromatography Methods and Compound Identification (Gc-ms And Nmr Analysis)mentioning

confidence: 99%

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

Sadgrove

Padilla-González

Green

et al. 2021

Plants

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“…Aldehyde 53 was easily prepared in three steps from lactone 18 via the silylation of the C3 hydroxyl group and reduction of the lactone to afford diol 52 , followed by the Swern oxidation of the resultant C16 and C22 hydroxyl groups. A vinylogous Mukaiyama aldol reaction between aldehyde 53 and 3‐methyl‐2‐( tert ‐butyl‐ dimethylsilyloxy)furan [ 35 ] in the presence of TiCl 4 produced butenolide 54 in 72% yield. [ 36 ] However, the stereochemistry at C22 and C23 was opposite to that of propindilactone G. Fortunately, the stereochemistry at C23 could be inverted by treating 54 with…”

Section: Resultsmentioning

confidence: 99%

Development of Biomimetic Synthesis of Propindilactone G^†

Wang

Chen

et al. 2020

Chin. J. Chem.

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of main observation and conclusion The natural product propindilactone G is a complex Schisandra nortriterpenoid with a unique 5/5/7/6/5 pentacyclic framework. This full paper describes the development of concise biomimetic synthesis of propindilactone G from a known steroid lactone. The key C19-OH intermediate was synthesized via Breslow and Suárez radical remote C-H functionalizations. Wagner-Meerwein rearrangement was subsequently utilized for the expansion of the B ring. To invert the configuration of the C10 tertiary alcohol, an intramolecular peroxide cyclization catalyzed by BF3•Et2O was devised. The 5/5 fused lactone system was then assembled in a biomimetic transesterification/oxa-Michael addition sequence. Our work should provide experimental support for the proposed biosynthetic pathway and facilitate investigation of the biological activities of propindilactone G.

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“…General methods : 1‐Octene, 1‐hexene, toluene, and Cu(OAc) 2 ⋅ H 2 O were purchased from Wako Pure Chemical Industries, Ltd. and used without further purification. Pd(OCOCF 3 ) 2 ,24 1 ,25 2 ,26 and 3 27 were synthesized by literature procedures. Acrylic acid (Nippon Shokubai Co., Ldt.)…”

Section: Methodsmentioning

confidence: 99%

Palladium‐Catalyzed Aerobic Intermolecular Cyclization of Acrylic Acid with 1‐Octene to Afford α‐Methylene‐γ‐butyrolactones: The Remarkable Effect of Continuous Water Removal from the Reaction Mixture and Analysis of the Reaction by Kinetic, ESI‐MS, and XAFS Measurements

Miyoshi¹,

Akatsuka²,

Okuoka³

et al. 2012

Chemistry A European J

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Further study of our aerobic intermolecular cyclization of acrylic acid with 1-octene to afford α-methylene-γ-butyrolactones, catalyzed by the Pd(OCOCF(3))(2)/Cu(OAc)(2)⋅H(2)O system, has clarified that the accumulation of water generated from oxygen during the reaction causes deactivation of the Cu cocatalyst. This prevents regeneration of the active Pd catalyst and, thus, has a harmful influence on the progress of the cyclization. As a result, both the substrate conversion and product yield are efficiently improved by continuous removal of water from the reaction mixture. Detailed analysis of the kinetic and spectroscopic measurements performed under the condition of continuous water removal demonstrates that the cyclization proceeds in four steps: 1) equilibrium coordination of 1-octene to the Pd acrylate species, 2) Markovnikov-type acryloxy palladation of 1-octene (1,2-addition), 3) intramolecular carbopalladation, and 4) β-hydride elimination. Byproduct 2-acryloxy-1-octene is formed by β-hydride elimination after step 2). These cyclization steps fit the Michaelis-Menten equation well and β-hydride elimination is considered to be a rate-limiting step in the formation of the products. Spectroscopic data agree sufficiently with the existence of the intermediates bearing acrylate (Pd-O bond), η(3)-C(8)H(15) (Pd-C bond), or C(11)H(19)O(2) (Pd-C bond) moieties on the Pd center as the resting-state compounds. Furthermore, not only Cu(II), but also Cu(I), species are observed during the reaction time of 2-8 h when the reaction proceeds efficiently. This result suggests that the Cu(II) species is partially reduced to the Cu(I) species when the active Pd catalytic species are regenerated.

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A short route to furanosesquiterpenes using a new siloxyfuran building block. The synthesis of freelingnite and dehydrolasiosperman

Cited by 57 publications

References 30 publications

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

Development of Biomimetic Synthesis of Propindilactone G^†

Palladium‐Catalyzed Aerobic Intermolecular Cyclization of Acrylic Acid with 1‐Octene to Afford α‐Methylene‐γ‐butyrolactones: The Remarkable Effect of Continuous Water Removal from the Reaction Mixture and Analysis of the Reaction by Kinetic, ESI‐MS, and XAFS Measurements

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A short route to furanosesquiterpenes using a new siloxyfuran building block. The synthesis of freelingnite and dehydrolasiosperman

Cited by 57 publications

References 30 publications

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)

Development of Biomimetic Synthesis of Propindilactone G†

Palladium‐Catalyzed Aerobic Intermolecular Cyclization of Acrylic Acid with 1‐Octene to Afford α‐Methylene‐γ‐butyrolactones: The Remarkable Effect of Continuous Water Removal from the Reaction Mixture and Analysis of the Reaction by Kinetic, ESI‐MS, and XAFS Measurements

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Development of Biomimetic Synthesis of Propindilactone G^†