Addition-addition-elimination mechanism of 1,3-dipole “dimerization”

Dorn, Helmut; Kreher, Thomas

doi:10.1016/0040-4039(88)85052-4

Cited by 18 publications

(6 citation statements)

References 11 publications

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“…When the two reagents were combined in equimolar quantities (Table 1, entry 2), the desired coupling product 3b was isolated in 38% yield. Dipole 2 is known to be capable of homo-dimerization [35], and examination of the crude NMR spectra for the reaction revealed the presence of this dimer along with unreacted 1a . We were gratified to find that simply increasing the amount of dipole to 3 equiv amplified the yield to 86%.…”

Section: Resultsmentioning

confidence: 99%

Dipolar addition to cyclic vinyl sulfones leading to dual conformation tricycles

Wong¹,

Brant²,

Barr³

et al. 2013

Beilstein J. Org. Chem.

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SummaryDipolar addition of cyclic azomethine imines with cyclic vinyl sulfones gave rise to functionalized tricycles that exhibited fluxional behavior in solution at room temperature. The scope of the synthetic methodology was explored, and the origin of the fluxional behavior was probed by NMR methods together with DFT calculations. This behavior was ultimately attributed to stereochemical inversion at one of two nitrogen centers embedded in the tricyclic framework. Two tetracycles were also synthesized, and the degree of signal-broadening in the NMR spectra was found to depend on the presence of substitution next to the inverting nitrogen center.

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Section: Resultsmentioning

confidence: 99%

Dipolar addition to cyclic vinyl sulfones leading to dual conformation tricycles

Wong¹,

Brant²,

Barr³

et al. 2013

Beilstein J. Org. Chem.

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“…On the other hand, limited examples of UV-promoted photoisomerization and photocyclization of azomethine iminium ions can be found in the literature . Nevertheless, only recently has reactivity of these unique substrates under visible-light photoredox catalytic conditions been demonstrated by Yang and co-workers.…”

mentioning

confidence: 99%

Visible-Light-Mediated α-Amino Alkylation of Azomethine Imines: An Approach to N-(β-Aminoalkyl)pyrazolidinones

2020

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Herein, a mild and robust photocatalytic protocol for the combination of amino and pyrazolidinone functionalities through a radical α-amino alkylation of azomethine iminium ions is demonstrated. This method presents a high functional group tolerance providing direct access to a large family of N-(β-aminoalkyl)pyrazolidinones in good to excellent yields, including the late-stage incorporation of the pyrazolidinone moiety to pharmaceutical ingredients. We propose a plausible scenario for the C–C bond-forming step which involves radical addition followed by a spin-center-shift event.

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“…1-Alkylidene-3-oxopyrazolidin-1-ium-2-ides (e.g., 2 in eq 1), developed by Dorn and Otto in 1968, are isolable and stable azomethine imines and have been used as 1,3-dipoles in the context of [3 + 2] cycloadditions, giving five-membered nitrogen-containing heterocycles. , Unfortunately, however, these useful 1,3-dipoles have never been engaged in a single-step formation of six-membered rings to date …”

mentioning

confidence: 99%

Palladium-Catalyzed [3 + 3] Cycloaddition of Trimethylenemethane with Azomethine Imines

2006

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A palladium-catalyzed [3 + 3] cycloaddition of trimethylenemethane (TMM) with azomethine imines has been developed to produce hexahydropyridazine derivatives under simple and mild conditions. The use of substituted TMM precursors highlights the difference of this system from previously reported [3 + 2] cycloaddition of TMMs under palladium catalysis. The present [3 + 3] cycloaddition reactions are also applicable to couplings with nitrones.

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Addition-addition-elimination mechanism of 1,3-dipole “dimerization”

Cited by 18 publications

References 11 publications

Dipolar addition to cyclic vinyl sulfones leading to dual conformation tricycles

Dipolar addition to cyclic vinyl sulfones leading to dual conformation tricycles

Visible-Light-Mediated α-Amino Alkylation of Azomethine Imines: An Approach to N-(β-Aminoalkyl)pyrazolidinones

Palladium-Catalyzed [3 + 3] Cycloaddition of Trimethylenemethane with Azomethine Imines

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