An Unusual Samarium Diiodide Mediated Reductive Ring Contraction of a Tricyclic Oxazine to a Highly-Functionalized Cyclopentane and Cyclobutane

McAuley, Barry J.; Nieuwenhuyzen, and Mark; Sheldrake, Gary N.

doi:10.1021/ol000057q

Cited by 23 publications

(7 citation statements)

References 6 publications

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“…[17,184] In a recent example, Sheldrake and Soissons have reported the selective opening of the thebaine skeleton from cycloadducts 181 by using samarium diiodide (Scheme 33). [185] Similar to other reactions of acylnitroso HDA cycloadducts, [186] samarium diiodide facilitated cleavage of the NÀO and CÀC bonds in one pot and provided the novel derivative 182.…”

Section: Amino Acid Analogues and Related Structuresmentioning

confidence: 92%

The Nitrosocarbonyl Hetero‐Diels–Alder Reaction as a Useful Tool for Organic Syntheses

Bodnar¹,

2011

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Organic transformations that result in the formation of multiple covalent bonds within the same reaction are some of the most powerful tools in synthetic organic chemistry. Nitrosocarbonyl hetero-Diels–Alder (HDA) reactions allow for the simultaneous stereospecific introduction of carbon–nitrogen and carbon–oxygen bonds in one synthetic step, and provide direct access to 3,6-dihydro-1,2-oxazines. This Review describes the development of the nitrosocarbonyl HDA reaction and the utility of the resulting oxazine ring in the synthesis of a variety of important, biologically active molecules.

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Section: Amino Acid Analogues and Related Structuresmentioning

confidence: 92%

The Nitrosocarbonyl Hetero‐Diels–Alder Reaction as a Useful Tool for Organic Syntheses

Bodnar¹,

2011

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“…In all cases, in addition to the concentration of the active Sm(II) species, the induction timethat is, the time after which the solution turned bluewas noted. However, it should be noted that the blue color of the reaction mixture does not indicate that the synthesis of SmI 2 is complete. − For example, we have found that blue solutions of SmI 2 in THF with concentrations lower than 0.005 M are visually indistinguishable from saturated solutions of 0.1 M in THF, which corresponds to at least a 20-fold difference in molarity.…”

Section: Resultsmentioning

confidence: 87%

“…For our study, we selected water, oxygen, and peroxide content, the quality of samarium metal, and the preparation procedure as the most likely factors affecting the formation of SmI 2 . − We started our investigation by studying in detail the synthesis of SmI 2 using Kagan’s method employing 1,2-diiodoethane as the oxidant.…”

Section: Resultsmentioning

confidence: 99%

“…Reports describing the negative influence of peroxide content in THF on the formation and stability of SmI 2 have also been published . A survey of the literature reveals many examples in which the yields of SmI 2 -mediated reactions are likely compromised due to low quality reagent that in turn arises from a poor understanding of the factors governing the synthesis of SmI 2 . Clearly, difficulties in preparing SmI 2 hinder the spread of its use in synthesis and perpetuate the myth that the reagent is difficult to work with.…”

Section: Introductionmentioning

confidence: 99%

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Preparation of Samarium(II) Iodide: Quantitative Evaluation of the Effect of Water, Oxygen, and Peroxide Content, Preparative Methods, and the Activation of Samarium Metal

2012

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Samarium(II) iodide (SmI(2)) is one of the most important reducing agents in organic synthesis. Synthetic chemistry promoted by SmI(2) depends on the efficient and reliable preparation of the reagent. Unfortunately, users can experience difficulties preparing the reagent, and this has prevented realization of the full synthetic potential of SmI(2). To provide synthetic chemists with general and reliable methods for the preparation of SmI(2), a systematic evaluation of the factors involved in its synthesis has been carried out. Our studies confirm that SmI(2) is a user-friendly reagent. Factors such as water, oxygen, and peroxide content in THF have little influence on the synthesis of SmI(2). In addition, the use of specialized glovebox equipment or Schlenk techniques is not required for the preparation of SmI(2). However, our studies suggest that the quality of samarium metal is an important factor and that the use of low quality metal is the main cause of failed preparations of the reagent. Accordingly, we report a straightforward method for activation of "inactive" samarium metal and demonstrate the broad utility of this protocol through the electron transfer reductions of a range of substrates using SmI(2) prepared from otherwise "inactive" metal. An investigation into the stability of SmI(2) solutions and an evaluation of commercially available solutions of the reagent is also reported.

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“…[17,184] In einem jüngeren Beispiel berichteten Sheldrake und Soissons über die selektive Öffnung des Thebaingerüsts in dem Cycloaddukt 181 mithilfe von Samariumdiiodid (Schema 33). [185] ¾hnlich wie im Fall anderer Reaktionen von Acylnitroso-HDA-Cycloaddukten [186] erleichtert Samariumdiiodid die Spaltung der N-O-und C-C-Bindungen im Eintopfverfahren, wodurch das neue Derivat 182 erhalten wird.…”

Section: Derivatisierung Von Naturstoffenunclassified

Hetero‐Diels‐Alder‐Reaktionen von Nitrosocarbonylverbindungen als nützliches Verfahren in der organischen Synthese

Bodnar¹,

Miller

2011

Angewandte Chemie

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Organische Transformationen, die in einem einzigen Reaktionsschritt mehrere kovalente Bindungen aufbauen, zählen zu den leistungsfähigsten Verfahren in der organischen Synthese. Hetero‐Diels‐Alder(HDA)‐Reaktionen von Nitrosocarbonylverbindungen ermöglichen die stereospezifische Einführung von Kohlenstoff‐Stickstoff‐ und Kohlenstoff‐Sauerstoff‐Bindungen in einem einzigen Syntheseschritt und bieten einen direkten Zugang zu 3,6‐Dihydro‐1,2‐oxazinen. In diesem Aufsatz werden die Entwicklung der Nitrosocarbonyl‐HDA‐Reaktion und der Nutzen der daraus erhältlichen Oxazinringe bei der Synthese verschiedener wichtiger biologisch aktiver Verbindungen beschrieben.

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An Unusual Samarium Diiodide Mediated Reductive Ring Contraction of a Tricyclic Oxazine to a Highly-Functionalized Cyclopentane and Cyclobutane

Cited by 23 publications

References 6 publications

The Nitrosocarbonyl Hetero‐Diels–Alder Reaction as a Useful Tool for Organic Syntheses

The Nitrosocarbonyl Hetero‐Diels–Alder Reaction as a Useful Tool for Organic Syntheses

Preparation of Samarium(II) Iodide: Quantitative Evaluation of the Effect of Water, Oxygen, and Peroxide Content, Preparative Methods, and the Activation of Samarium Metal

Hetero‐Diels‐Alder‐Reaktionen von Nitrosocarbonylverbindungen als nützliches Verfahren in der organischen Synthese

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