Asymmetric synthesis and absolute stereochemistry of a labdane-type diterpenoid isolated from the rhizomes of Isodan yuennanensis

Deng, Heping; Cao, Wei; Zhang, Zhijiang; Liu, Bo

doi:10.1039/c6ob00750c

Cited by 14 publications

(4 citation statements)

References 38 publications

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“…Since Viktor Mayer’s discovery of oximes approximately one and a half centuries ago, synthetic routes leading to these species have been widely developed. In metal-free organic chemistry, the main types of high-yield reactions leading to oximes include the condensation of RR′CO (R′ = alkyl, aryl, or H) with hydroxylamine (for recent works, see refs − ) or O -substituted hydroxylamines (giving oxime ethers; for recent works, see refs and ), nitrosation of aliphatic compounds (for recent work, see ref ), or reduction of nitro species (for recent works, see refs − ).…”

Section: Metal-mediated Generation Of Oximesmentioning

confidence: 99%

Metal-Involving Synthesis and Reactions of Oximes

et al. 2017

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This review classifies and summarizes the past 10-15 years of advancements in the field of metal-involving (i.e., metal-mediated and metal-catalyzed) reactions of oximes. These reactions are diverse in nature and have been employed for syntheses of oxime-based metal complexes and cage-compounds, oxime functionalizations, and the preparation of new classes of organic species, in particular, a wide variety of heterocyclic systems spanning small 3-membered ring systems to macroheterocycles. This consideration gives a general outlook of reaction routes, mechanisms, and driving forces and underlines the potential of metal-involving conversions of oxime species for application in various fields of chemistry and draws attention to the emerging putative targets.

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Section: Metal-mediated Generation Of Oximesmentioning

confidence: 99%

Metal-Involving Synthesis and Reactions of Oximes

et al. 2017

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“…In accordance with the retrosynthetic analysis, reduction of the lactone in compound 14 and selective protection of the resulting diol with acetic anhydride afforded compound 19 in quantitative yield (Scheme ) . Treatment of alcohol 19 with thionyl chloride in the presence of pyridine furnished the unsaturated intermediate 20 .…”

Section: Resultsmentioning

confidence: 77%

“…Wittig olefination afforded the terminal alkene 25 , and subsequent coupling with 2‐methyl acrolein by cross metathesis resulted in the formation of α,β‐unsaturated ketone 26 . Final Wittig olefination accomplished the synthesis of the natural labdane‐type diterpenoid 5 , whose characterization data were identical to those of the natural sample …”

Section: Resultsmentioning

confidence: 95%

Asymmetric Synthesis of Hispidanin A and Related Diterpenoids

Cao

Deng

Sun

et al. 2018

Chemistry A European J

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We report on our accomplishment of the asymmetric synthesis of hispidanin A and its natural precursor, a labdane diterpenoid. In the first generation of synthesis, a semi-synthesis strategy was employed to construct a labdane-type diterpenoid, a natural precursor of hispidanin A, in which Barton's photolytic remote functionalization was employed as a key transformation. In addition, the totarane-type dienophile counterpart was derived from commercially available (-)-scalareol. In the second generation of synthesis, key elements included an iron-catalyzed radical cascade to access the labdane-type diene on the basis of hydrogen atom transfer, and an enantioselective cationic polyene cyclization furnished the totarane-type dienophile. Reaction optimization and mechanistic analysis of the radical cascade reaction was conducted. Furthermore, the [4+2] cycloaddition reaction was achieved in excellent yield and selectivity under thermal conditions, which has been rationalized by using DFT transition-state analysis and paved the way for final accomplishment of the total synthesis of hispidanin A.

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“…Accordingly, for an expedient synthesis of labdane-type diene 5, we selected (3aR)-(+)-sclareolide, a commercially cheap material, as the starting compound (Scheme 2). 5 Reduction of the lactone and selective protection of the primary alcohol with acetic anhydride afforded compound 10. The following four steps were conducted to invert the stereochemistry of its tertiary alcohol.…”

Section: Total Synthesis Of Hispidanin Amentioning

confidence: 99%

Total Synthesis of Natural Terpenoids: Inspired but Not Limited by Biohypothesis

Chen

Liu

2018

Synlett

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This account describes our studies on the total synthesis of several natural terpenoids based on our modified biosynthetic hypothesis. Compared to the originally proposed biosynthetic hypothesis, the modified ones proved to be more practicable for the formation of hispidanin A, a dimeric diterpenoid, and sarcandrolide J and shizukaol D, two dimeric sesquiterpenoids, from a viewpoint of chemical reactivity. Moreover, a cascade reaction involving intermolecular and intramolecular cycloaddition was facilitated to expeditiously accumulate molecular complexity in the total synthesis of bolivianine, a sesterterpenoid, on the basis of a modified biohypothesis.1 Introduction2 Total Synthesis of Hispidanin A3 Total Syntheses of Bolivianine and Isobolivianine4 Total Syntheses of Sarcandrolide J and Shizukaol D5 Conclusion

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Asymmetric synthesis and absolute stereochemistry of a labdane-type diterpenoid isolated from the rhizomes of Isodan yuennanensis

Cited by 14 publications

References 38 publications

Metal-Involving Synthesis and Reactions of Oximes

Metal-Involving Synthesis and Reactions of Oximes

Asymmetric Synthesis of Hispidanin A and Related Diterpenoids

Total Synthesis of Natural Terpenoids: Inspired but Not Limited by Biohypothesis

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