An approach to an asymmetric synthesis of stemofoline

Thomas, Eric J.; Vickers, Clare

doi:10.1016/j.tetasy.2009.03.002

Cited by 15 publications

(7 citation statements)

References 23 publications

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“…The observed stereoisomers were identified as syn -adducts 10a , 12a (isolated as a mixture), and anti -aduct 11a respectively, by elaboration to known compounds . In comparison to propionate imino-aldol reactions, which are often highly diastereoselective, modest levels of stereoselectivity have been noted previously for imino-aldol reactions of methyl and para -methoxybenzyl esters of functionalized straight-chain carboxylic acids. ,, …”

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confidence: 82%

Total Syntheses of (−) Epilupinine and (−)-Tashiromine Using Imino-Aldol Reactions

et al. 2011

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Short routes to enantiomerically pure indolizidine and quinolizidine alkaloids have been developed using imino-aldol reactions of enolates derived from phenyl 5-chlorovalerate. High levels of syn selectivity (dr ∼13-16:1) were obtained using lithium enolates of phenyl esters in combination with tert-butylsulfinyl imines. The imino-aldol adducts were deprotected and cyclized to afford (-)-epilupinine ((-)-2) and (-)-tashiromine ((-)-1) in two further steps.

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confidence: 82%

Total Syntheses of (−) Epilupinine and (−)-Tashiromine Using Imino-Aldol Reactions

et al. 2011

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“…1,13,14 However, despite considerable effort, the only two accounts of the total syntheses of these alkaloids are Kende’s synthesis of (±)-isostemofoline ( 7 ) 15 and Overman’s syntheses of (±) -1 and (±) -6 . 16 Other interesting approaches toward these alkaloids have also been reported.…”

Section: Introductionmentioning

confidence: 99%

“…16 Other interesting approaches toward these alkaloids have also been reported. 13 For example, Thomas applied an intramolecular Mannich reaction to construct the skeleton of stemofoline ( 2 ), 13e,d and Gin prepared the core structure of stemofoline by a novel process that featured an intramolecular dipolar cycloaddition. 13a,e …”

Section: Introductionmentioning

confidence: 99%

Asymmetric formal total synthesis of the stemofoline alkaloids: the evolution, development, and application of a catalytic dipolar cycloaddition cascade

et al. 2013

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A formal synthesis of didehydrostemofoline and isodidehydrostemofoline has been accomplished by preparing an intermediate in the Overman synthesis of these alkaloids from commercially available 2-deoxy-D-ribose. The work presented in this account chronicles the evolution of our explorations to identify the optimal steric and electronic control elements necessary to generate the tricyclic core structure of these alkaloids in a single operation from an acyclic precursor. The key step in the synthesis is a novel dipolar cycloaddition cascade sequence that is initiated by cyclization of a rhodium-derived carbene onto the nitrogen atom of a proximal imine group to generate an azomethine ylide that then undergoes spontaneous cyclization via dipolar cycloaddition. The synthesis features several other interesting reactions, including a Boord elimination to prepare a chiral allylic alcohol, a highly diastereoselective Hirama-Itô cyclization, and a useful modification of the Barton decarboxylation protocol.

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“…Despite these efforts, [12,13] the only total syntheses are Kende’s synthesis of (±)-isostemofoline ( 5 ) in 1999 [14] and Overman’s syntheses of (±) -1 and (±) -4 in 2003. [15] Each of the Kende and the Overman strategies relied upon clever cascade processes to construct the bridged polycyclic core of these alkaloids.…”

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confidence: 99%

Enantioselective Formal Total Syntheses of Didehydrostemofoline and Isodidehydrostemofoline through a Catalytic Dipolar Cycloaddition Cascade

et al. 2012

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Sweet to the Core Enantioselective formal total syntheses of the Stemona alkaloids didehydrostemofoline and isodidehydrostemofoline were accomplished in 24 steps from commercially available 2-deoxy-d-ribose. The synthesis features a novel cascade of reactions culminating in an intramolecular dipolar cycloaddition to form the cage-like, tricyclic core of the stemofoline alkaloids from an acyclic diazo imine intermediate.

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An approach to an asymmetric synthesis of stemofoline

Cited by 15 publications

References 23 publications

Total Syntheses of (−) Epilupinine and (−)-Tashiromine Using Imino-Aldol Reactions

Total Syntheses of (−) Epilupinine and (−)-Tashiromine Using Imino-Aldol Reactions

Asymmetric formal total synthesis of the stemofoline alkaloids: the evolution, development, and application of a catalytic dipolar cycloaddition cascade

Enantioselective Formal Total Syntheses of Didehydrostemofoline and Isodidehydrostemofoline through a Catalytic Dipolar Cycloaddition Cascade

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