Total Synthesis of (−)-Palasonin and (+)-Palasonin and Related Chemistry

Dauben, William G.; Lam, Joe Y. L.; Guo, Zhen

doi:10.1021/jo960210n

Cited by 50 publications

(16 citation statements)

References 24 publications

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“…(±)-Palasonine, however, could be synthesized by Diels-Alder reaction of furan to citraconic anhydride (entry 4) only at high pressure followed by catalytic hydrogenation. This Diels-Alder reaction does not substantially proceed at atmospheric pressure and high temperature or catalyzed by LiClO 4 [40].…”

Section: Synthetic Applicationsmentioning

confidence: 93%

The Effect of Pressure on Organic Reactions

Klärner¹,

Wurche²

2000

J. prakt. Chem.

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The utility of high pressure for the understanding of chemical reactions and its application in organic synthesis is shown for cycloadditions (inter‐ and intramolecular Diels‐Alder reactions, 1,3‐dipolar and [2+2] cycloadditions), cheletropic reactions and pericyclic rearrangements (Cope and Claisen rearrangements and electrocyclizations). The origin of the effect of pressure on chemical reactions is discussed. Especially, the change in the packing coefficient during cyclization of chains and the effect of electrostriction on reactions, in which charged species are generated, contribute substantially to a volume contraction leading to a powerful pressure‐induced acceleration of such reactions. Finally, the effect of pressure on free‐radical reactions (homolytic bond dissociations and quinone oxidations) is described.

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Section: Synthetic Applicationsmentioning

confidence: 93%

The Effect of Pressure on Organic Reactions

Klärner¹,

Wurche²

2000

J. prakt. Chem.

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“…Interestingly, no problems in terms of product fragmentation or instability were reported in the development of this reaction, which was successfully performed on a multigram scale. In general, [4+2] cycloaddition reactions that involved citraconic anhydride ( 11 ) are significantly rarer that those of its simpler symmetrical congener, maleic anhydride ( 14 ) …”

Section: Resultsmentioning

confidence: 99%

“…In general, [4+ +2] cycloaddition reactions that involved citraconic anhydride (11)a re significantly rarer that those of its simpler symmetrical congener,maleic anhydride (14). [12][13][14]…”

Section: Resultsmentioning

confidence: 99%

Synthesis of the Bicyclic Lactone Core of Leonuketal, Enabled by a Telescoped Diels–Alder Reaction Sequence

Grant

Brimble

Furkert

2018

Chemistry An Asian Journal

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The Diels-Alder cycloaddition reaction has become established as a fundamental approach for the preparation of complex natural products; however, successful application of the intermolecular Diels-Alder cycloaddition reaction to the synthesis of particularly congested scaffolds remains surprisingly problematic. Inspired by the terpenoid spiroketal natural product leonuketal, a challenging telescoped reaction sequence has been realized to access the core [2.2.2]-bicyclic lactone ring system and its [3.2.1] isomer. Our four-step, protecting-group-free process required detailed investigation to circumvent the problems of adduct fragmentation and intermediate instability. Successful solution of these practical issues, along with unambiguous structural determination of the target structures, provide useful insights that will facilitate future applications of the Diels-Alder cycloaddition reaction to challenging, highly congested molecular scaffolds and ongoing synthetic efforts towards this natural product.

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“…Although dimethyl maleic anhydride does not add to furan even at pressures up to 40 [19] or 60 kbar [21], Dauben's laboratory [22] showed that (±)-palasonin 24 could be synthesized in two steps and in moderate yield (57%). They used the high pressure Diels-Alder procedure (15 kbar, 8 h) as the key step in the reaction between citraconic anhydride 31 and furan, followed by hydrogenation of the (±)-dehydropalasonin 32 in nonprotic solvent over 10% palladium on carbon (Scheme 8).…”

Section: Furan Cycloadditionsmentioning

confidence: 99%

“…Two isomers were isolated after hydrogenation in an approximate 1:1 ratio and assigned as exo-regioisomers 48a and 48b, in an analogy to the Diels-Alder reaction between citraconic anhydride and furan which gives only the exo-adduct [22]. Two isomers were isolated after hydrogenation in an approximate 1:1 ratio and assigned as exo-regioisomers 48a and 48b, in an analogy to the Diels-Alder reaction between citraconic anhydride and furan which gives only the exo-adduct [22].…”

Section: Scheme 10 Synthesis Of Dimethoxycantharidin Derivative 41mentioning

confidence: 99%