Synthesis of Linear Tetraquinanes by [3+2] Cycloaddition, Chemoselective Allylation of 7-Ketonorbornene, and Ring-Rearrangement Metathesis as Key Steps

Kotha, Sambasivarao; Agrawal, Arpit

doi:10.1055/s-0042-1751365

Cited by 4 publications

(5 citation statements)

References 38 publications

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“…Surprisingly, when the same transformation was performed under MWI conditions for 20 min., we obtained the desired [3 + 2] cycloaddition product 26, a useful precursor to RRM. The compound 26 on treatment with G-II catalyst [34] gave RRM products 15 and 16 (Scheme 3).…”

Section: Chemistryselectmentioning

confidence: 99%

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Linear Tetraquinanes by Microwave Assisted [3+2] Cycloaddition and Ring‐Rearrangement Metathesis

Kotha

Agrawal

2023

ChemistrySelect

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Herein, an improved synthetic strategy to linear tetraquinanes is reported via a [3 + 2] cycloaddition and ring-rearrangement metathesis as key steps. The linear tetraquinanes reported earlier were synthesized in a nine step sequence with an overall yield of 9 % while the same tetraquinanes are now prepared in four steps with a 3-fold increase in overall yield of 29 %. Failure of the conventional [3 + 2] cycloaddition using allyltriisopropyl-silane was overcome by using microwave irradiation (MWI) conditions which is performed for the first time for this purpose. The strategy reported here does not involve any protection and deprotection steps and can be helpful for the synthesis of polyquinane based natural products and synthesis of medicinally important targets.

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Section: Chemistryselectmentioning

confidence: 99%

“…Hence, we are interested in constructing such structures and to this end recently, we reported two different linear tetraquinanes using a [3 + 2] cycloaddition and RRM as key steps (Figure 3). [34] Our earlier strategy involve nine steps and since then we are interested in an improved route to these compounds.…”

Section: Introductionmentioning

confidence: 99%

Linear Tetraquinanes by Microwave Assisted [3+2] Cycloaddition and Ring‐Rearrangement Metathesis

Kotha

Agrawal

2023

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“…The compound 6 was subjected to ringrearrangement metathesis 10 (RRM) sequence using G-II catalyst (Figure 1) to obtain stereochemically rich tetraquinane derivatives 7 and 8 (Scheme 2). 11 3 Regioselectivity…”

Section: Chemoselectivitymentioning

confidence: 99%

Selectivity: A Goal for Synthetic Economy

Kotha¹,

Ansari²,

Gupta³

2022

Synlett

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Chemical reactivity plays a major role in understanding several aspects of selectivity. Therefore, we present a plethora of reactions that demonstrate our efforts in exploiting interesting cases of selectivity observed in the past three decades. Among them, chemoselectivity, regioselectivity and steroselectivity are discussed. Strain, steric factors, and separations of the reacting functionalities are displayed as prominent features in generating selectivity.

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“…In view of our continuous interest in CÀ C bond formation reactions [44][45][46][47][48] such as olefin-metathesis, [49][50][51][52][53][54][55][56][57][58][59] we envisioned a new synthetic strategy to assemble fused 5/5/n (n = 6, 7, 8)tricyclic systems by adopting a simple and rapid protocol which involve RRM as a key step and exo-dicyclopentadiene-1-one (exo-DCPD-1-one; 11) as a key building block.…”

Section: Introductionmentioning

confidence: 99%

Synthetic Studies to exo‐Ring‐Junction based Fused 5/5/n‐Tricyclic Systems: Access to A, B, C‐Ring System of Longeracinphyllin A, Himalenine D, and Daphnipaxiamine A.

2023

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We report a short synthetic approach to various tricyclic systems that are present in several diquinane‐based natural products starting with a readily available exo‐dicyclopentadiene‐1‐one. To this end, we have successfully assembled a fused 5/5/7‐tricyclic enone via ring‐rearrangement metathesis as a key step. The strategy has been further extended to synthesize the 1,3‐dihydroxy and then 1‐keto‐3‐hydroxy derivatives by utilizing regio‐ and stereoselective epoxidation and ring‐rearrangement metathesis reactions as key steps. All these target compounds are found to be present in diquinane‐based natural products such as longeracinphyllins A, himalenine D and daphnipaxianine A, etc. Moreover, the newly synthesized tricyclic compounds matches the exact ring‐junction stereochemistry (5/5‐exo) of these natural products. Hence, the synthetic studies disclosed here may be useful in the synthesis of biologically significant natural products and in the drug design. The newly synthesized molecules were characterized by NMR and HRMS data. Some of these structures were confirmed by a single crystal X‐ray diffraction studies.

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Synthesis of Linear Tetraquinanes by [3+2] Cycloaddition, Chemoselective Allylation of 7-Ketonorbornene, and Ring-Rearrangement Metathesis as Key Steps

Cited by 4 publications

References 38 publications

Linear Tetraquinanes by Microwave Assisted [3+2] Cycloaddition and Ring‐Rearrangement Metathesis

Linear Tetraquinanes by Microwave Assisted [3+2] Cycloaddition and Ring‐Rearrangement Metathesis

Selectivity: A Goal for Synthetic Economy

Synthetic Studies to exo‐Ring‐Junction based Fused 5/5/n‐Tricyclic Systems: Access to A, B, C‐Ring System of Longeracinphyllin A, Himalenine D, and Daphnipaxiamine A.

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