Concise Formal Syntheses of the <i>Amaryllidaceae</i> Alkaloids (±)‐Tazettine and (±)‐6a‐Epipretazettine: Construction of the Core Skeleton via Tandem Intramolecular Oxidative Friedel–Crafts/Aza‐Michael Reaction

Ma, Dawei; Zhao, Chang‐Qiu; Li, Huilin; Qi, Jing; Zhang, Ling; Xu, Shiyan; Xie, Xingang; She, Xuegong

doi:10.1002/asia.201200964

Cited by 12 publications

(2 citation statements)

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“…Chiral pyrrolidines and tetrahydropyrans are important structural units for their massive appearance in bioactive molecules, such as octahydropyrano[2,3- c ]pyrrole derivatives . In 2004, Johnson and co-workers attempted to synthesize these compounds through the reaction of aziridines with 3,4-dihydropyran in the presence of a stoichiometric amount of zinc chloride.…”

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confidence: 99%

Asymmetric [3 + 2] Cycloaddition of 2,2′-Diester Aziridines To Synthesize Pyrrolidine Derivatives

et al. 2017

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A highly diastereo- and enantioselective [3 + 2] cycloaddition of 2,2′-diester aziridines with 3,4-dihydropyran derivatives and acyclic enol ethers has been established. Various optically active octahydropyrano[2,3-c]pyrrole and 3-methoxypyrrolidine derivatives were generated in moderate to high yields (up to 94%) and good stereoselectivities (>19:1 dr, up to 95.5:4.5 er). The methodology was also applied in the highly diastereoselective synthesis of d-galactal derivatives. The absolute configuration of the octahydropyrano[2,3-c]pyrroles showed that the reactions using 3,4-dihydropyran and 6-alkyl-substituted ones as substrates gave reversed diastereoselection in the final cyclization step.

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confidence: 99%

Asymmetric [3 + 2] Cycloaddition of 2,2′-Diester Aziridines To Synthesize Pyrrolidine Derivatives

et al. 2017

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“…With enough key intermediate 3 in hand, the stage was set to the critical bioinspired oxidative Friedel–Crafts reaction. Although there are many cases of phenol oxidative dearomatization/Friedel–Crafts reaction applied in natural product synthesis, , in our substrate, it is considered to be challenging for two aspects. The first one is the expected intramolecular Friedel–Crafts should occur across the THF ring to form the seven-membered ring with an all-carbon quaternary center as linkage, while the presumed cation intermediate 2 is in situ generated.…”

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confidence: 99%

Bioinspired Total Synthesis of Gymnothelignan N

Zhang

Xie

et al. 2014

Org. Lett.

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Bioinspired total synthesis of gymnothelignan N was accomplished in 13 steps and 6.7% overall yield. The synthesis features a syn Evans aldol reaction, an intramolecular hydrogenative dehydration reaction, and a phenol oxidative dearomatization/Friedel-Crafts reaction, which provides a new plausible biosynthetic pathway for the gymnothelignans and other symbiotic members. Meanwhile, another tetrahydrofuran-type lignan beilschmin A was also synthesized.

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Palladium‐catalyzed Oxa‐[4+2] Annulation of para‐Quinone Methides

et al. 2017

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A palladium‐catalyzed oxa‐[4+2] annulation of para‐quinone methides with allyl carbonates bearing a nucleophilic alcohol side chain has been developed. This method provided an efficient strategy to the construction of 2‐oxaspiro‐cyclohexadienones via 1,6‐conjugated addition‐mediated allylation in moderate to good yields. Preliminary results on asymmetric derivatives promised potential in the synthesis of enantioenriched frameworks.magnified image

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Concise Formal Syntheses of the Amaryllidaceae Alkaloids (±)‐Tazettine and (±)‐6a‐Epipretazettine: Construction of the Core Skeleton via Tandem Intramolecular Oxidative Friedel–Crafts/Aza‐Michael Reaction

Cited by 12 publications

References 57 publications

Asymmetric [3 + 2] Cycloaddition of 2,2′-Diester Aziridines To Synthesize Pyrrolidine Derivatives

Asymmetric [3 + 2] Cycloaddition of 2,2′-Diester Aziridines To Synthesize Pyrrolidine Derivatives

Bioinspired Total Synthesis of Gymnothelignan N

Palladium‐catalyzed Oxa‐[4+2] Annulation of para‐Quinone Methides

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