The high pressure mediated intramolecular Diels-Alder reaction of furan dienes: a synthetic approach towards daphnanes.

BURRELL, S. J.; Derome, Andrew E.; Edenborough, Michael; Harwood, Laurence M.; Leeming, S. A.; Isaacs, Neil S.

doi:10.1016/s0040-4039(00)98969-x

Cited by 37 publications

(6 citation statements)

References 9 publications

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“…These compounds are challenging and interesting targets for synthetic chemists. Quite a few efforts have been dedicated to this direction, ,,,− but up to now only one total synthesis has been completed by Wender’s group . This excellent work has been extensively reviewed in 1998, 2003, and 2007 .…”

Section: Daphnane Diterpenoid Orthoesters (Ddos)mentioning

confidence: 99%

“…The first effort toward the synthesis of the tricyclic system via the [X f BC f ABC] approach was made by Harwood and coworkers (Scheme 3). 194 Furan 130a underwent an IMDA reaction at 14 kbar to give a mixture of endo (131a) and exo (132a) adducts, in which the exo adduct (132a) that possessed the correct stereochemistry at C-8 of daphnane diterpenes was formed as a kinetic product. When a doubly activated E-dienophile (130b) was used as an IMDA substrate, selectivity (25% of 131b vs 5% of 132b) was observed but the yield of 132b was rather low.…”

Section: Strategies For Construction Of the Daphnane Diterpene Skeletonmentioning

confidence: 99%

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Plant Orthoesters

2009

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Section: Daphnane Diterpenoid Orthoesters (Ddos)mentioning

confidence: 99%

Section: Strategies For Construction Of the Daphnane Diterpene Skeletonmentioning

confidence: 99%

Plant Orthoesters

2009

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“…The first example of a seven-membered carbocycle fused to a cyclohexene, generated through the IMDA reaction of a furan, has very recently been reported. 54 As a preliminary study with overtones relating to the daphnane diterpenes of general structure 115, intramolecular closure of enone furan 116 was envisioned. While all attempts to promote this cycloaddition using either thermal or Lewis acid based conditions were unsuccessful, subjecting 116 to 14 kbars of pressure at room temperature in CH2C12 afforded endo-117 and exo-118.…”

mentioning

confidence: 99%

Five-membered heteroaromatic rings as intermediates in organic synthesis

Lipshutz¹

1986

Chem. Rev.

1,155

322

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“…1985 年, Harwood 课题组利用分子内的 Diels-Alder 反应作为关键步骤发展了 X-BC-ABC 构建瑞香烷型二萜骨架的策略 [10] (图式 5). 1-甲基呋喃 48 经五步转化以基于该类 Diels-Alder 的特性, 1988 年, Harwood 课题组发展了亲双烯体两端都具有吸电子基的 Diels-Alder 反应(图式 6) [11] , 而且为了减少产物在常压下发生逆 Diels-Alder 反应, 粗产物立即在钯、硫酸钡、氢气条件下发生氢化反应.…”

Section: [X-bc-abc]策略unclassified

Synthetic Progress of Daphnane-type Diterpenoids

Liu¹,

Feng²,

Liu³

2016

Acta Chim. Sinica

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Daphnane diterpenoids usually embrace a 5/7/6-tricyclic ring system with poly-hydroxyl groups located at C3, C4, C5, C9, C13, C14, C20 and some special ones have a characteristic orthoester motif located at C9, C13, C14. The daphnane diterpenoids can be categorized into daphnetoxins, 12-hydroxydaphnetoxins, 1-alkyldaphnanes, resiniferonoids, genkwanines and rediocides, based on the oxygen containing functions at rings B and C, as well as the substitution pattern of the ring A. Besides, some daphniphyllum alkaloids are qualified with daphnane and seco-daphnane skeletons. Up to now, more than 100 daphnane diterpenoids have been isolated from Thymelaeaceae and Euphorbiaceae. Their structures have been determined on the basis of chemical correlation, NMR, X-ray diffraction, IR and other spectral analysis. The in-vitro and in-vivo experiments of these compounds have shown that they bear a wide range of biological activities including anti-HIV, anticancer, anti-leukemic, neurotrophic, pesticidal and cytotoxic effects. The biogenic hypothesis postulated that the daphnane-type and the tigliane type diterpenoids can be derived from a common intermediate, and that the tigliane-type can be transferred into the daphnane-type diterpenoids. There have been few papers on the total syntheses of daphnane diterpenoids owing to the synthetic challenges derived from their dense, highly oxygenated and polycyclic skeletons. However, numerous synthetic endeavors have been made in constructing core structures of daphnane diterpenoids based on various methodologies. In this paper, we focus on reviewing the synthetic efforts which have been made for daphnane diterpenoids, and we divide the main body of this paper into two parts, total syntheses and the related methodologies. The first part contains the asymmetric total synthesis of (＋)-resiniferatoxin, the gateway synthesis of C6-C7-epi-yuanhuapin, and the biomimetic synthesis of (±)-methyl-homosecodaphniphyllate. The second part is classified according to the sequence of constructing the ABC core of daphnane diterpenoids, including the [X-BC-ABC] approach, the [X-AB-ABC] approach, the [AX-ABC] approach, the [CX-ABC] approach, the [A'B'C'-ABC] approach and the [X-ABC] approach. Keywords daphnane; diterpenoid; (＋)-resiniferatoxin; total synthesis; synthetic methodology 1 引言瑞香烷型二萜类天然产物主要分布在瑞香科和大戟科植物中, 具有 5/7/6 三环骨架 1, 通常在 C3、C4、 C5、C9、C13、C14、C20 位置有羟基, 在 C9、C13、 C14 具有特定的原酸酯结构. 根据 B 环和 C 环的氧化形式以及 A 环的取代形式, 可将已知的瑞香烷型二萜天然产物(图 1)分为六类 [1] : daphnetoxins 2、12-hydroxydaphnetoxins 3、1-alkyldaphnanes 4、resiniferonoids 5、 genkwanines 6 和 rediocides 7; 其中, daphnetoxins 通常在 A 环具有 α-β 不饱和酮结构, 且 B 环具有 C5β 羟基、 C20 羟基、C6α-C7α 环氧结构; 12-hydroxydaphnetoxins 相对于 daphnetoxins 在 C12 处多一个含氧官能团 OR, 并且 OR 通常为酰氧基; 1-alkyldaphnanes 通常具有饱和的 A 环, 并且原酸酯烷基链末端和 A 环 C1 之间具有一个大环; resiniferonoids 相对于 daphnetoxins 而言, A 环具有 α-β 不饱和酮结构, B 环 C5 为亚甲基且 C6-C7 之间为双键, C20 为羟基或者酰氧基; genkwanines 通常在 B 环 C6-C7 之间具有双羟基, 并且饱和 A 环 C3 以及 B 环 C20

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The high pressure mediated intramolecular Diels-Alder reaction of furan dienes: a synthetic approach towards daphnanes.

Cited by 37 publications

References 9 publications

Plant Orthoesters

Plant Orthoesters

Five-membered heteroaromatic rings as intermediates in organic synthesis

Synthetic Progress of Daphnane-type Diterpenoids

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