Azabicycles construction: the transannular ring contraction with N-protected nucleophiles

Rizzo, Antonio; Harutyunyan, Syuzanna R.

doi:10.1039/c4ob01311e

Cited by 20 publications

(6 citation statements)

References 67 publications

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“…We also report that subsequent Baeyer–Villiger oxidation of the bicyclic nitrocyclopropanes followed by enolization with TMSOTf/Et 3 N resulted in the novel formation of tetrahydro-2 H -cyclopenta[ b ]furans in a highly stereoselective manner. This transformation is regarded to proceed through a ring cleavage/expansion reaction of the cyclopropane moiety followed by a novel nucleophilic transannular cyclization by the nitronate anion to the lactone carbonyl function.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Synthesis of Bicyclic Nitrocyclopropanes from Primary Nitro Compounds and Stereoselective Formation of Tetrahydro-2H-cyclopenta[b]furans via Ring Expansion/Cyclization Reaction

et al. 2016

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Optically active bicyclic nitrocyclopropanes are readily prepared from primary chiral nitro compounds, prepared by the conjugate addition of propionaldehyde to a nitro alkene in the presence of proline-derived organocatalysts. The one-step cyclopropanation took place smoothly in a highly stereoselective manner regardless of the stereogenic center adjacent to the allylic unit. Although the allylation reaction catalyzed by BF3·OEt2 provides a mixture of two possible diastereomers, subsequent oxidation of the alcoholic carbon after the formation of nitrocyclopropanes gave diastereomerically pure single products. As a result, separation of the diastereomers during the reaction sequence is unnecessary. Baeyer-Villiger oxidation of the bicyclic nitrocyclopropane ketones followed by enolization resulted in stereoselective formation of a novel cyclopenta[b]furan ring in good yield via ring expansion followed by transannular nucleophilic cyclization.

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Section: Introductionmentioning

confidence: 99%

Asymmetric Synthesis of Bicyclic Nitrocyclopropanes from Primary Nitro Compounds and Stereoselective Formation of Tetrahydro-2H-cyclopenta[b]furans via Ring Expansion/Cyclization Reaction

et al. 2016

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“…The transannular transformations of cyclic molecules represent a powerful method to access complex polycyclic compounds, rapidly enhancing the molecular diversity and complexity . In the present work, the transannular Alder-ene rearrangement of the nine-membered 1,4-oxazonine products 3 was investigated to afford the fused-bicyclic hexahydropyranopyrroles 4 (Scheme ).…”

mentioning

confidence: 99%

Synergistic Pd(0)/Rh(II) Dual Catalytic [6 + 3] Dipolar Cycloaddition for the Synthesis of Monocyclic Nine-Membered N,O-Heterocycles and Their Alder-ene Rearrangement to Fused Bicyclic Compounds

2021

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The catalytic construction of a monocyclic medium-sized N,O-heterocyclic ring represents a formidable challenge in organic synthesis. Herein we report the synergistic palladium(0)/rhodium(II) dual catalytic cycloaddition of vinylpropylene carbonates with N-sulfonyl-1,2,3-triazoles to afford monocyclic nine-membered N,O-heterocycles. The catalytically generated 1,6-dipole-equivalent zwitterionic π-allyl palladium(II) complex and the 1,3-dipole-equivalent α-imino rhodium(II) carbenoid intermediate react with each other in a formal [6 + 3] dipolar cycloaddition to furnish nine-membered oxazonines, which can be transformed into cis-fused [4.3.0] bicyclic compounds via a transannular Alder-ene rearrangement. The tandem one-pot cycloaddition/Alder-ene rearrangement sequence is also possible.

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“… , Generally, the synthetic methodologies for bicyclic compounds include cycloaddition , or annulation reactions, which are well-documented in the literature. Another efficient and step-economical method is transannular ring contraction . However, most of the transannular ring contraction reports involve syntheses of bicyclic structures containing fused rings of different sizes (e.g., 6,5- or 7,5-bicycles) or the same size (e.g., 6,6-bicycles) …”

mentioning

confidence: 99%

Diastereoselective Synthesis of Bicyclo[3.3.0]octenones by Copper-Catalyzed Transannular Ring-Closing Reaction

Kang

Yang

et al. 2022

Org. Lett.

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A novel and efficient copper-catalyzed transannular ring-closing reaction of eight-membered rings has been developed that provides a straightforward way to synthesize bicyclo[3.3.0]octane derivatives in good yields. Mechanistic studies revealed that the reaction pathway might involve chlorination followed by the Kornblum reaction. Readily accessible starting materials and good functional group tolerance make this procedure attractive.

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Azabicycles construction: the transannular ring contraction with N-protected nucleophiles

Cited by 20 publications

References 67 publications

Asymmetric Synthesis of Bicyclic Nitrocyclopropanes from Primary Nitro Compounds and Stereoselective Formation of Tetrahydro-2H-cyclopenta[b]furans via Ring Expansion/Cyclization Reaction

Asymmetric Synthesis of Bicyclic Nitrocyclopropanes from Primary Nitro Compounds and Stereoselective Formation of Tetrahydro-2H-cyclopenta[b]furans via Ring Expansion/Cyclization Reaction

Synergistic Pd(0)/Rh(II) Dual Catalytic [6 + 3] Dipolar Cycloaddition for the Synthesis of Monocyclic Nine-Membered N,O-Heterocycles and Their Alder-ene Rearrangement to Fused Bicyclic Compounds

Diastereoselective Synthesis of Bicyclo[3.3.0]octenones by Copper-Catalyzed Transannular Ring-Closing Reaction

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