Stereocontrolled synthesis of highly functionalised spirocyclic pyrans

Hobson, Stephen J.; Marquez, Rodolfo

doi:10.1039/b611737f

Cited by 13 publications

(3 citation statements)

References 40 publications

(11 reference statements)

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“…The ground-breaking work by Lefebvre sparked subsequent methodological investigations on this oxygenative procedure. [45][46][47][48][49] Most importantly, the synthetic community quickly absorbed this straightforward and tolerant approach as a valuable alternative to the bromonium-induced Achmatowicz-type reactions and, hence, the m-chloroperbenzoic acid mediated furylcarbinol ring expansion developed into a well-explored key step that was used in a variety of total syntheses. [50][51][52][53][54][55] In particular, the in situ ketalization in the oxidative ring enlargement of di-or polyhydroxylated furans, pioneered by Martin, 27 has attracted much attention and found application in numerous total synthetic scenarios.…”

Section: Scheme 16 Proposed Epoxidation Pathway In the Peracid-inducementioning

confidence: 99%

The Achmatowicz Rearrangement – Oxidative Ring Expansion of Furfuryl Alcohols

2015

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Over the years, the oxidative ring enlargement of furfuryl alcohols, known as the Achmatowicz reaction, has been developed into a powerful and versatile synthetic tool for the preparation of 6-hydroxypyranones. This review provides a comprehensive collection of the various ways to perform Achmatowicz rearrangement reactions and explores the role of this ring-expansion process in contemporary organic synthesis. 1 Introduction 2 Classical Methods and Variants 3 Single-Electron-Transfer Oxidations 4 Metal-Catalyzed Ring Expansions 5 Photolytic Oxygenations 6 Enzymatic Transformations 7 Conclusions

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Section: Scheme 16 Proposed Epoxidation Pathway In the Peracid-inducementioning

confidence: 99%

The Achmatowicz Rearrangement – Oxidative Ring Expansion of Furfuryl Alcohols

2015

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“…151 Conversions higher then 95% were achieved in 20 min reactions at 180 • C for EWG substituents up to 280 • C for ED substituents. 153 No side-chain epoxidation of (183) was detected, de based on NMR analysis, and consequently the hydroxy-directed oxidation was efficient in giving a completely selective rearrangement. 152 Achmatowicz rearrangement of furyl carbinols (183) affords, with high diastereoselectivity (α:β = 8:1) and good yields, alkenylated pyrans (184), which could be efficiently allylated at the anomeric carbon, giving (185), as a route to spirocyclic pyrans (Scheme 50).…”

Section: Isomerizationsmentioning

confidence: 99%

“…A new tandem cleavage-cyclization reaction of tetrahydroisoquinoline derivatives has been reported for the synthesis of benzoazocines. 131 5,7-Diaryl-2-fluoro-4H -1,3-diazepines (156) have been synthesized from 3-aryl-substituted 2H -azirines (153) and difluorocarbene. 130 The regioselectivity in this iminocyclopropene rearrangement has also been disclosed.…”

Section: Rearrangements Involving Ring Openingmentioning

confidence: 99%

Molecular Rearrangements: Part 2. Other Reactions

Brandi

Gensini

2010

Organic Reaction Mechanisms · 2006

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The formation of α-phenyl-β-halovinyl cation, β-phenyl-α-halovinyl cation, and also the halogen-bridged and the spirocyclic phenyl-bridged cations, as intermediates of protonation of phenylethynyl halides, or of halogen addition to phenylethynes, has been evaluated by DFT at the B3LYP/6-31+G(d) level and, for comparison in representative cases, by B3LYP/6-311++G(d,p). 1 Structural and mechanistic studies of the lithium diisopropylamide (LDA)-mediated anionic Fries rearrangements of aryl carbamates have been described. 2 Substituents at the meta position of the arene (H, OMe, F) and the dialkylamino moiety of the carbamate (Me 2 N, Et 2 N, and i-Pr 2 N) markedly influence the relative rates of ortholithiation and subsequent Fries rearrangement. The mechanism of the Fries rearrangement of aryl formates promoted by boron trichloride has been studied by means of 1 H, 2 H, and 11 B NMR spectroscopy and DFT calculations. 3 After the formation of a 1:1 substrate -Lewis acid adduct, the rearrangement proceeds in two steps, beginning with the cleavage of the ester bond and the release of formyl chloride in situ, which, in turn, acts as a formylating agent, introducing 451

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Oxidative Cleavage of Furans

Merino

2015

Organic Reactions

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Oxidative ring cleavage reactions of furans constitute a group of important transformations that have found wide utility in synthetic organic chemistry. These processes have been used to prepare a variety of 1,4‐dicarbonyl compounds including 1,4‐dioxoalkenes, 4‐oxoalkenals, 4‐oxoalkenoic acids, and their derivatives such as 4‐hydroxybutenolides and 2,5‐dialkoxydihydrofurans. Oxidations of furfuryl alcohols (Achmatowicz reaction) and furfuryl amines (aza‐Achmatowicz reaction) provide access to highly functionalized heterocyclic structures that have been employed as intermediates in synthetic routes for the preparation of complex molecules including carbohydrates and alkaloids. Complete oxidative degradation of the furan ring affords carboxylic acids; thus the oxygen heterocycle has served as a masked carboxyl group in many synthetic studies. These transformations and their applications in total syntheses are covered in this chapter.

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Stereocontrolled synthesis of highly functionalised spirocyclic pyrans

Cited by 13 publications

References 40 publications

The Achmatowicz Rearrangement – Oxidative Ring Expansion of Furfuryl Alcohols

The Achmatowicz Rearrangement – Oxidative Ring Expansion of Furfuryl Alcohols

Molecular Rearrangements: Part 2. Other Reactions

Oxidative Cleavage of Furans

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