DMAP Promoted Tandem Addition Reactions Forming Substituted Tetrahydroxanthones

Castillo-Contreras, Emmanuel B.; Dake, Gregory R.

doi:10.1021/ol5002945

Cited by 24 publications

(9 citation statements)

References 52 publications

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“…During the preparation of substituted tetrahydroanthrones different propargyl alcohols were transformed into ynones by Swern oxidation. 34 For instance, double oxidation took place when alcohols 29 were oxidized under typical Swern conditions giving ynones 30 in variable yields (Scheme 9). The ynones were further transformed into the related tetrahydroanthrones by a DMPA-catalyzed tandem nucleophilic addition process.…”

Section: From Propargylic Alcoholsmentioning

confidence: 99%

Conjugated Ynones in Organic Synthesis

2019

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This review article will consider the preparation and application of ynones in synthetic organic chemistry. Concerning the preparation of these bifunctional compounds, several methodologies starting from propargyl alcohols, acyl derivatives, both by using alkynylmetal reagents or by transition metal (mainly palladium and copper) catalyzed alkynylations, carbon monoxide (carbonylation of terminal alkynes and alkenes), and other substrates will be discussed. The reactivity and synthetic applications of ynones will be focused on conjugate additions with boron-, carbon-, nitrogen-, oxygen-, and other heteroatom-containing nucleophiles, as well as radicals. Then, cycloaddition processes will include [2 + 2] cycloadditions, [3 + 2] 1,3-dipolar cycloadditions (with azides, nitrones, azomethine imines and ylides, nitrile oxides, diazo compounds, and other dipoles), and [4 + 2] cycloadditions (mainly Diels–Alder-type reactions). The reduction of the triple bond, addition to the carbonyl group (using carbon- and heteronucleophiles and reductions), and other not so commonly used processes (such as aldol reactions, cyclizations, and isomerizations) will be considered at the end.

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Section: From Propargylic Alcoholsmentioning

confidence: 99%

Conjugated Ynones in Organic Synthesis

2019

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“…In both cases, starting materials were totally recovered. We next conducted the reaction using lithium diisopropylamide (LDA) as the base at −78 °C . Attempts were made by varying the reaction temperature, reaction time, and the order of addition of the reagents.…”

Section: Resultsmentioning

confidence: 99%

“…We next conducted the reaction using LDA as the base at -78 °C. 18 Attempts were made by varying the reaction temperature, reaction time and the order of addition of the reagents. Unfortunately, this reaction was found to be not reproducible with the formation of trace amounts of the expected compound along with various amounts of allene 9.…”

Section: Scheme 3 Synthesis Of Aldehydementioning

confidence: 99%

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Total Synthesis of Tedarene A

et al. 2017

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Tedarene A is a macrocyclic diaryl ether heptanoid isolated from the marine sponge Tedania ignis showing an inhibitory effect against nitric oxide production. The first total synthesis of tedarene A was achieved starting from the commercially available 3-(4-methoxyphenyl)propan-1-ol in nine steps and 15.3% overall yield. The synthetic sequence featured an E,Z-dienic bond introduction and a macrocyclization under Ullman conditions. During the synthesis, the E,E-isomer of tedarene A was also obtained and fully characterized.

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“…The reactions were either complicated or decomposed when hydroquinine, MeONa, TBAF, Cs 2 CO 3 , or NaOH was used (for more details, see the SI). Inspired by the Dake group's work, 24 DMAP was used and yielded the expected 6-endo product. We also inferred that the existence of the highly reactive free phenol made the corresponding compounds unstable under most of the aforementioned conditions.…”

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confidence: 99%

Convergent Synthesis of Kibdelone C

Dai

Shen

et al. 2018

Org. Lett.

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The synthesis of kibdelone C, a polycyclic natural xanthone isolated from a soil actinomycete, was achieved through a convergent approach. A 6π-electrocyclization was applied to construct the highly substituted dihydrophenanthrenol fragment (B-C-D ring). InBr-promoted lactonization was employed to build the isocoumarin ring, which served as a common precursor for the formation of isoquinolinone ring (A-B ring). A key DMAP-mediated oxa-Michael/aldol cascade reaction was developed to install the tetrahydroxanthone fragment (E-F ring). This approach provides a new solution to prepare its derivatives and structurally related natural products.

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DMAP Promoted Tandem Addition Reactions Forming Substituted Tetrahydroxanthones

Abstract: Substituted tetrahydroxanthones are constructed using a DMAP-promoted tandem nucleophilic addition process. The reaction yields range from 39% to 73%. Disubstituted tetrahydroxanthones are generated as a ∼2.3:1 mixture of diastereomers favoring the formation of the trans-isomer.

Cited by 24 publications

References 52 publications

Conjugated Ynones in Organic Synthesis

Conjugated Ynones in Organic Synthesis

Total Synthesis of Tedarene A

Convergent Synthesis of Kibdelone C

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