Total Synthesis of Sesquiterpenes, 1970‐79

Heathcock, Clayton H.; Graham, Samuel; Pirrung, Michael C.; Plavac, Frank; White, Charles T.

doi:10.1002/9780470129685.ch1

Cited by 30 publications

(31 citation statements)

References 464 publications

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“…[118][119][120] However, this method places the angular methyl and the isopropenyl groups trans to each other. Other approaches where these two groups are cis to each other as required in lairdinol 51 are also known and are briefly elaborated in Figure 2.2.…”

Section: Enantiospecific Total Synthesis Of Lairdinol a †mentioning

confidence: 99%

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Total Synthesis of Depsilairdin

Ward

Pardeshi

2010

J. Org. Chem.

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The total synthesis of depsilairdin, a host-selective phytotoxin isolated from Leptosphaeria maculans (the causal agent of blackleg disease of oilseed Brassicas), has been achieved by N-terminal extension of a suitably protected derivative of the hitherto unknown amino acid (2S,3S,4R)-3,4-dihydroxy-3-methyl-proline (Dhmp) followed by esterification with lairdinol A. The latter esterification, complicated by the sterically hindered nature of the carboxyl group, was accomplished by a novel method involving reaction of the 1-hydroxybenzotriazole (HOBt) derived active ester with the bromomagnesium alkoxide of lairdinol A. Three depsilairdin analogues were also prepared by replacing the Dhmp residue with L-proline and cis-and trans-4-hydroxy-L-proline. Phytotoxicity assays showed that the analogues were nontoxic to both blackleg-susceptible (brown mustard) and -resistant (canola) plants, suggesting that the presence of the Dhmp residue in depsilairdin is important for its host-selective toxicity toward brown mustard.

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Section: Enantiospecific Total Synthesis Of Lairdinol a †mentioning

confidence: 99%

“…116,117 This class of natural products has attracted considerable attention from synthetic chemists. 118,119 Several approaches have been documented in the literature concerning the synthesis of eudesmane type sesquiterpenes. The decalin ring system can be constructed via a…”

Section: Enantiospecific Total Synthesis Of Lairdinol a †mentioning

confidence: 99%

Total Synthesis of Depsilairdin

Ward

Pardeshi

2010

J. Org. Chem.

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“…A variety of approaches to construct this fused 5,7 ring system [1,2] and to synthesize representative natural products of this family have been elaborated. [3] Apart from the utilization of rearrangement reactions of -for example -decalin precursors, most of the synthesis strategies for such hydroazulenes (also named bicyclo[5. 3.0]-decanes) have started with the five-membered ring and elab-lar aldol condensation of which gave the tricycle 15.…”

Section: Introductionmentioning

confidence: 99%

“…[3] Apart from the utilization of rearrangement reactions of -for example -decalin precursors, most of the synthesis strategies for such hydroazulenes (also named bicyclo[5. 3.0]-decanes) have started with the five-membered ring and elab-lar aldol condensation of which gave the tricycle 15. The oxa bridge of the oxatricyclic enone 15 was cleaved by hydrogenolysis in the presence of palladium/carbon catalyst to give the 6-hydroxydecahydroazulen-4-one 16.…”

Section: Introductionmentioning

confidence: 99%

Synthetic Approaches to Hydroazulenes and Guaianes through [4 + 3] Cycloadditions of Oxyallyl Intermediates

et al. 2006

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Building blocks for syntheses of guaiane and secoguaiane sesquiterpenoids were prepared by the title reaction. 4-(3-Methylfuran-2-yl)butan-2-one (1) was obtained in five steps from methyl 3-methylfuran-2-carboxylate (4), and treatment of 1 with pentachloroacetone and sodium 2,2,3,3-tetrafluoropropoxide in 2,2,3,3-tetrafluoropropan-1-ol produced a [4 + 3] cycloadduct that was dechlorinated without prior isolation to give the oxabicyclic diketone 2 in a low yield. A better route to diketone 2 was via the oxabicycle 10b, prepared in a high yield from 2-(but-3-en-1-yl)-3-methylfuran (9) and pentachloroacetone, followed by dechlorination. Treatment of 2 with dilute methanolic potassium hydroxide resulted in the cleavage of the oxa bridge, with formation of 3,8-dimethylazulen-4-ol (11). Catalytic hydrogenation of 2 afforded the saturated oxabicyclic diketone 14, intramolecu-

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“…The total synthesis of these natural products is not a new challenge, 2 but the construction of appropriately substituted decalin carbon skeletons is still a relevant synthetic task. Recently, many new examples of eudesmane sesquiterpenes have been isolated from natural sources and several new synthetic methodologies have been described.…”

Section: Introductionmentioning

confidence: 99%