Cyclopropanone hemiacetals

Salaün, Jacques

doi:10.1021/cr00058a002

Cited by 85 publications

(45 citation statements)

References 38 publications

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“…[10] However, the equivalent treatment of cyclopropanone dimethyl acetal failed to yield cycloaddition products under the same conditions. [11] Thus, it appears that the transformation of the cyclopropanone into an oxyallyl cation is required for this cycloaddition to proceed. Even so, cycloaddition reactions between dienes and cyclopropanes are not "forbidden" processes: Several examples of the reaction of vinylcyclopropanes with C=C or C=X bonds to afford cycloheptane derivatives have been described.…”

mentioning

confidence: 99%

Donor–Acceptor Cyclopropanes as Three‐Carbon Components in a [4+3] Cycloaddition Reaction with 1,3‐Diphenylisobenzofuran

et al. 2008

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confidence: 99%

Donor–Acceptor Cyclopropanes as Three‐Carbon Components in a [4+3] Cycloaddition Reaction with 1,3‐Diphenylisobenzofuran

et al. 2008

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“…Conversely, intramolecular nucleophilic attack of the pendant amino group to the cyclopropanone carbonyl by the same face where the thioether is located proceeds with easily accessible activation barriers (ΔG ‡ TS2 = 14-17 kcal mol -1 ) to give first zwitterionic (HAzw) then neutral (HA) hemiaminal bicyclic adducts. As shown previously, 37 such transformations are strongly favored for cyclopropanones due to the significant strain release exerted by the carbonyl sp 2 → sp 3 rehybridization, despite the formation of 2-thia-5-azabicyclo[4.1.0]heptane structures. The OH-deprotonated form of these bicyclic intermediates (HA -) undergo fast ring-expansion reactions resembling those occurring in Favorskii rearrangements [37][38] (ΔG ‡ TS3 = 6-8 kcal mol -1 ).…”

Section: Cyclopropenone Ring-opening After Double Nucleophilic Attackmentioning

confidence: 54%

Selective N-Terminal Cysteine Protein Modification with Cyclopropenones

Istrate¹,

Navo²,

Sousa³

et al. 2020

Preprint

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<div><div><div><p>Protein conjugates are valuable tools to create therapeutics, such as antibody-drug conjugates, or to study biological processes. Despite a number of protein conjugation strategies having been developed over recent years, the ability to modify one specific amino acid on a protein in the presence of other side chains with similar reactivity remains a challenge. We used the reaction between a monosubstituted cyclopropenone (CPO) probe and the 1,2-aminothiol of an N-terminal cysteine to give a stable 1,4-thiazepa-5-none linkage under mild, biocompatible conditions. The method relies on the ability of cyclopropenones to ring-open after sequential sulfhydryl and α-amine conjugation to be truly specific for N-terminal cysteine. We show that our CPO probes selectively label N-terminal cysteine containing peptides and proteins even in the presence of internal, solvent-exposed cysteines, which can be subsequently modified by using conventional cysteine modification reagents. The ability to distinguish and specifically target N-terminal cysteine residues on a protein will facilitate the construction of elaborate multi-labelled bioconjugates.</p></div></div></div>

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“…Very few isolable acyclic hemiacetals have been reported and most are stabilized by strong electron withdrawing groups, steric hindrance, or intermolecular hydrogen bonding . A few other examples include the hemiacetal of lauraldehyde and lauryl alcohol, acid treated poly (vinyl butyral),, and some dipeptides and tripeptides .…”

Section: Resultsmentioning

confidence: 99%

An isolable acyclic hemiacetal of ansamitocin P‐3

Segraves¹,

Yazzie²,

Deese³

2012

Magnetic Reson in Chemistry

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During impurity analysis of maytansinol (2), produced from the reduction of ansamitocin P-3 (AP-3, 1), a surprisingly stable acyclic hemiacetal (4) was isolated. A combination of 1D and 2D NMR experiments, along with liquid chromatography-mass spectrometry data was used to confirm the structure. Comparison of NMR data to the previously reported bridged acetal (3), a by-product of AP-3 reduction, supports reassignment of the latter to the former. Additionally, ROESY data, in conjunction with minimum energy calculations, support intramolecular hydrogen bonding that is involved in stabilizing the hemiacetal. This report adds another example to the very short list of isolable acyclic hemiacetals.

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Cyclopropanone hemiacetals

Cited by 85 publications

References 38 publications

Donor–Acceptor Cyclopropanes as Three‐Carbon Components in a [4+3] Cycloaddition Reaction with 1,3‐Diphenylisobenzofuran

Donor–Acceptor Cyclopropanes as Three‐Carbon Components in a [4+3] Cycloaddition Reaction with 1,3‐Diphenylisobenzofuran

Selective N-Terminal Cysteine Protein Modification with Cyclopropenones

An isolable acyclic hemiacetal of ansamitocin P‐3

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