Diastereoselective cycloadditions of chiral homoallylic alcohols with benzonitrile oxide

Kociolek, Martin G.; Hongfa, Chayanant

doi:10.1016/s0040-4039(03)00100-x

Cited by 10 publications

(11 citation statements)

References 21 publications

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“…Magnesium salts have been shown to accelerate nitrile oxide cycloadditions to allylic alcohols . This methodology has been useful for the synthesis of enantiopure β-hydroxy ketones and γ-amino alcohols .…”

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confidence: 99%

Transition Structures of Diastereoselective 1,3-Dipolar Cycloadditions of Nitrile Oxides to Chiral Homoallylic Alcohols

2007

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Transition structures of the 1,3-dipolar cycloaddition of substituted nitrile oxides with chiral homoallylic alcohols were explored with density functional theory (B3LYP/6-311+G(d,p)+CPCM(dichloromethane)//B3LYP/6-31+G(d)). The diastereoselectivity observed in these reactions was explained. The anti product is favored in both the thermal and magnesium-mediated reactions. Selectivity is predicted to increase in the presence of magnesium, in agreement with experimental results. The energetics of the magnesium-mediated reaction are similar to those previously found for allylic alcohols. [structure: see text].

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confidence: 99%

Transition Structures of Diastereoselective 1,3-Dipolar Cycloadditions of Nitrile Oxides to Chiral Homoallylic Alcohols

2007

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“…The nitrile oxide thus generated can coordinate with the eliminated magnesium salt. Magnesium mediated nitrile oxide cycloaddition was also reported by Kociolek et al [16]. Cycloaddition of homo allylic alcohol 7 with nitrile oxide generated in situ from benzoyl oximinoyl chloride in the presence of ethyl magnesium chloride proceeded at -78 ºC to yield the corresponding isoxazolines with good to moderate diastereoselectivitives for the syn isomer 8 (Scheme 3).…”

Section: Nitrile Oxide Cycloaddition To Allylic and Homoallylic Alcoholsmentioning

confidence: 52%

Recent Advances in Nitrile Oxide Cycloadditions. Synthesis of Isoxazolines

Sibi¹

2011

COS

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Synthesis of novel heterocyclic compounds continues to be an important and challenging task. Isoxazolines are one such class of heterocyclic molecules of significance, since they are frequently found in many compounds that show significant biological activity. They are also of importance since they can be easily transformed into important functional groups. Nitrile oxide cycloaddition with carbon dipolarophiles represents an easy route to the synthesis of these molecules. Research groups over the past decades have established novel protocols and methods for the synthesis of isoxazolines via dipolar cycloaddition. This review will highlight the success that has been achieved in this field since 2000.

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“…[20] During the course of our studies, magnesium-mediated nitrile oxide cycloadditions with homoallylic alcohols have been communicated. [21] Although the influence of different substituents on the homoallylic alcohol was examined, these studies were limited to the use of benzonitrile oxide. Aliphatic nitrile oxides, known to be more susceptible towards dimerization, were not investigated.…”

Section: Entrymentioning

confidence: 99%

“…[21] Their assignment of the relative stereochemistry of b-hydroxy isoxazolines is based on the comparison of the chemical shifts of the C 5 hydrogen atom in the 1 H NMR spectrum with analogous bmethyl ester isoxazolines, compounds described by Panek et al [29] who demonstrated that the chemical shift of the C 5 hydrogen atom of the syn-diastereomer of the examined bmethyl ester isoxazolines occurs at slightly higher field than the corresponding signal of the anti-diastereomer. In 1 H NMR spectra of b-hydroxy isoxazolines we found the major diastereotopic signal for the C 5 hydrogen atom shifted slightly upfield compared to the analogous minor diastereotopic signal.…”

Section: Confirmation Of the Relative Configurationmentioning

confidence: 99%

Polyketide Building Blocks via Diastereoselective Nitrile Oxide Cycloadditions with Homoallylic Alcohols and Monoprotected Homoallylic Diols

Lohse-Fraefel

Carreira

2009

Chemistry A European J

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A modular approach to Delta(2)-isoxazolines, latent aldol adducts and polyketide building blocks, is reported. The magnesium-mediated, hydroxyl-directed method allows for the diastereoselective access to a wide variety of masked beta-hydroxy ketones, starting from readily available aliphatic and aromatic oximes, homoallylic alcohols and monoprotected homoallylic diols. The utility of the prepared Delta(2)-isoxazolines as polyketide building blocks is demonstrated by their ready conversion into the corresponding beta-hydroxy ketones. The anti-diastereoselectivity of the reaction was established by derivatization, NOE studies and comparison of known compounds. A rationale for the observed diastereoselectivity is proposed.

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Diastereoselective cycloadditions of chiral homoallylic alcohols with benzonitrile oxide

Cited by 10 publications

References 21 publications

Transition Structures of Diastereoselective 1,3-Dipolar Cycloadditions of Nitrile Oxides to Chiral Homoallylic Alcohols

Transition Structures of Diastereoselective 1,3-Dipolar Cycloadditions of Nitrile Oxides to Chiral Homoallylic Alcohols

Recent Advances in Nitrile Oxide Cycloadditions. Synthesis of Isoxazolines

Polyketide Building Blocks via Diastereoselective Nitrile Oxide Cycloadditions with Homoallylic Alcohols and Monoprotected Homoallylic Diols

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