Synthesis of the azatricyclic ACD ring system of calyciphylline A-type Daphniphyllum alkaloids via a nonstabilized azomethine ylide generated by desilylation

Ma, Ding; Cheng, Hang; Huang, C. Y.; Xu, Liang

doi:10.1016/j.tetlet.2015.03.097

Cited by 34 publications

(5 citation statements)

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“…The azatricyclic [6-5-7] ring system 320 was created via the intramolecular [3+2]-cycloaddition reaction of azomethine ylide generated from aldehyde 318 and N -(trimethylsilyl)methyl iminium salt 319 in the presence of a catalytic amount of phosphoric acid in DMF as a solvent ( Scheme 108 ) [ 148 ].…”

Section: Cyclic Unsaturated 2π-electron Componentsmentioning

confidence: 99%

Azomethine Ylides—Versatile Synthons for Pyrrolidinyl-Heterocyclic Compounds

et al. 2023

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Azomethine ylides are nitrogen-based three-atom components commonly used in [3+2]-cycloaddition reactions with various unsaturated 2π-electron components. These reactions are highly regio- and stereoselective and have attracted the attention of organic chemists with respect to the construction of diverse heterocycles potentially bearing four new contiguous stereogenic centers. This review article complies the most important [3+2]-cycloaddition reactions of azomethine ylides with various olefinic, unsaturated 2π-electron components (acyclic, alicyclic, heterocyclic, and exocyclic ones) reported over the past two decades.

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Section: Cyclic Unsaturated 2π-electron Componentsmentioning

confidence: 99%

Azomethine Ylides—Versatile Synthons for Pyrrolidinyl-Heterocyclic Compounds

et al. 2023

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“…Intra- and intermolecular cyclization occur via dimerization, − Michael-type addition, − and electrocyclization, − but primarily through [3 + 2] cycloaddition with dipolarophiles. − First reported by Huisgen in the early 1960s, − [3 + 2] dipolar cycloadditions are efficient and regioselective methods for forming cyclic compounds, typically following Woodward–Hoffmann rules . Moreover, Houk’s theoretical and computational work into [3 + 2] cycloadditions has established a mechanistic framework for synthetic control. − Strategic use of 1,3-dipolar cycloadditions has been pivotal in the synthesis of several natural products (Figure ), including daphniphyllum 1 , stemofoline 2 , daphnilactone 3 , pancracine 4 , epibatidine 5 , and 5-deoxymubironine 6 . For the synthesis of the natural products in Figure , and other pyrrolidine motifs of pharmaceutical interest, it is necessary to identify and efficiently synthesize the requisite dipolar azomethine ylide.…”

Section: Introductionmentioning

confidence: 99%

“…25 Moreover, Houk's theoretical and computational work into [3 + 2] cycloadditions has established a mechanistic framework for synthetic control. 26−29 Strategic use of 1,3-dipolar cycloadditions has been pivotal in the synthesis of several natural products (Figure 1), including daphniphyllum 1, 30 stemofoline 2, 31 daphnilactone 3, 32 pancracine 4, 33 epibatidine 5, 34 and 5deoxymubironine 6. 35 For the synthesis of the natural products in Figure 1, and other pyrrolidine motifs of pharmaceutical interest, it is necessary to identify and efficiently synthesize the requisite dipolar azomethine ylide.…”

Section: Introductionmentioning

confidence: 99%

Multi-Ion Bridged Pathway of N-Oxides to 1,3-Dipole Dilithium Oxide Complexes

et al. 2021

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Roussi's landmark work on the generation of 1,3dipoles from tertiary amine N-oxides has not reached its full potential since its underlying mechanism is neither well explored nor understood. Two competing mechanisms were previously proposed to explain the transformation involving either an iminium ion or a diradical intermediate. Our investigation has revealed an alternative mechanistic pathway that explains experimental results and provides significant insights to guide the creation of new Noxide reagents beyond tertiary alkylamines for direct synthetic transformations. Truhlar's M06-2x functional and Møller−Plesset second-order perturbation theory with Dunning's [jul,aug]-cc-pv[D,T]z basis sets and discrete-continuum solvation models were employed to determine activation enthalpies and structures. During these mechanistic explorations, we discovered a unique multiion bridged pathway resulting from the rate-determining step, which was energetically more favorable than other alternate mechanisms. This newly proposed mechanism contains no electrophilic intermediates, strengthening the reaction potential by broadening the reagent scope and limiting the possible side reactions. This thoroughly defined general mechanism supports a more direct route for improving the use of N-oxides in generating azomethine ylide−dilithium oxide complexes with expanded functional group tolerance and breadth of chemistry.

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“…Synthesis of the ACD Ring System of Calyciphylline A-type Alkaloids. In 2015, Xu and coworkers 164 reported a synthesis of the [6,5,7] azatricyclic core of calyciphylline A-type alkaloids based on an intramolecular [3 + 2] cycloaddition involving a nonstabilized azomethine ylide intermediate. The first step involved the carbomethoxylation of 192, followed by reduction of the carbonyl group, mesylation, and DBU-mediated elimination to afford unsaturated ester 361 (Scheme 49).…”

Section: Synthesis Of Calyciphylline A-type Alkaloidsmentioning

confidence: 99%

Recent Progress in the Chemistry of Daphniphyllum Alkaloids

2017

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Daphniphyllum is an evergreen species known since 1826. After initial systematic investigations, more than 320 members of this family have been isolated, which comprise complex and fascinating structures. Unique azapolycyclic architectures containing one or more quaternary stereocenters render these alkaloids synthetically challenging. This review covers efforts toward the synthesis of Daphniphyllum alkaloids spanning the period from 2005 to the beginning of 2016, including reported biological activities as well as the isolation of new members of this genus.

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Synthesis of the azatricyclic ACD ring system of calyciphylline A-type Daphniphyllum alkaloids via a nonstabilized azomethine ylide generated by desilylation

Cited by 34 publications

References 50 publications

Azomethine Ylides—Versatile Synthons for Pyrrolidinyl-Heterocyclic Compounds

Azomethine Ylides—Versatile Synthons for Pyrrolidinyl-Heterocyclic Compounds

Multi-Ion Bridged Pathway of N-Oxides to 1,3-Dipole Dilithium Oxide Complexes

Recent Progress in the Chemistry of Daphniphyllum Alkaloids

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