Mechanistic Criteria for Cation Radical Reactions: Aminium Salt-Catalyzed Cyclopropanation

Yueh, Wang; Bauld, Nathan L.

doi:10.1021/ja00126a007

Cited by 48 publications

(39 citation statements)

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“…Glassware was oven dried at 140 °C for at least 2 h prior to use, and allowed to cool under vacuum. LFe 3 (OAc)(OTf) 2 , 8a Fe(N(SiMe 3 ) 2 ) 2, 21 benzyl potassium, 22 1- H -3-phenyl pyrazole (HPhPz), 23 anhydrous [NBu 4 ][F] 24 , and [(2,4-Br-C 6 H 3 ) 3 N][SbCl 6 ] 25 were prepared according to literature procedures. [(4-Br-C 6 H 4 ) 3 N][OTf] was prepared according to a modified literature procedure.…”

Section: Methodsmentioning

confidence: 99%

Tetranuclear Fe Clusters with a Varied Interstitial Ligand: Effects on the Structure, Redox Properties, and Nitric Oxide Activation

Reed

Agapie

2017

Inorg. Chem.

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A new series of tetranuclear iron clusters displaying an interstitial μ4-F ligand was prepared for comparison to μ4-O analogs. With a single NO coordinated as a reporter of small molecule activation, the μ4-F clusters were characterized in five redox states, from FeII3{FeNO}8 to FeIII3{FeNO}7, with N–O stretching frequencies ranging from 1680 cm−1 to 1855 cm−1, respectively. Despite accessing more reduced states with an F− bridge, a two electron reduction of the distal Fe centers is necessary for the μ4-F clusters to activate NO to the same degree as the μ4-O system; consequently, NO reactivity is observed at more positive potentials with μ4-O than μ4-F. Moreover, the μ4-O ligand better translates redox changes of remote metal centers to diatomic ligand activation. The implication for biological active sites is that the higher charge bridging ligand is more effective in tuning cluster properties, including the involvement of remote metal centers, for small molecule activation

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Section: Methodsmentioning

confidence: 99%

Tetranuclear Fe Clusters with a Varied Interstitial Ligand: Effects on the Structure, Redox Properties, and Nitric Oxide Activation

Reed

Agapie

2017

Inorg. Chem.

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“…We believed that the biogenic dimerization of 5 proceeds through a radical cyclization mechanism, and sought to provide support for the single-electron transfer (SET) 181-185 biosynthetic hypothesis put forth by Molinski and Romo. 49,50 Our biomimetic synthesis of ageliferins ( 11 ) involves the use of a SET-oxidation for setting up its cyclohexenyl core skeleton.…”

Section: The Higher Order Pyrrole-imidazole Alkaloidsmentioning

confidence: 99%

Syntheses of cyclic guanidine-containing natural products

Chen

2015

Tetrahedron

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Naturally occurring guanidine derivatives frequently display medicinally useful properties. Among them, the higher order pyrrole-imidazole alkaloids, the dragmacidins, the crambescidins/batzelladines, and the saxitoxins/tetradotoxins have stimulated the development of many new synthetic methods over the past decades. We provide here an overview of the syntheses of these cyclic guanidine-containing natural products.

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“…In the same solvent (acetonitrile) the p value for the plot of the log of the relative rate constants for the Diels-Alder cycloadditions vs (T+ is -4.16, i.e., approximately 83 % of a unit of positive charge is present in this transition state. It is of further interest that similar studies have been carried out for the cation radical cyclopropanation of these same substrates, and the p value (-4.56) represents 91 'YO of the full unit of positive charge [72]. The rate determining step of these reactions has been found to be the cycloaddition step, so that even in the TS of cycloadditions, 83-91 % of the charge remains on the stilbene moiety, consistently with a reaction having an early transition state.…”

Section: Electronmentioning

confidence: 99%