New and Facile Substitution Reactions at Tertiary Carbon

Kornblum, Nathan; Davies, Thomas M.; Earl, Gary W.; Holy, Norman L.; Kerber, Robert C.; Musser, Michael T.; Snow, Donald H.

doi:10.1021/ja00979a067

Cited by 45 publications

(5 citation statements)

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“…C H 2 D 0 , -With a,p-dinitrocumene an even more striking set of results is observed; some of these are shown in Figure 2 reactions are noteworthy not only because they involve substitution at a tertiary carbon but also because the displacement of a nitro group from a saturated carbon atom is unprece-Actually, the aliphatic nitro group is but one of a number of functions which ordinarily d o not behave as leaving groups and yet are readily displaced in these radical anion substitution processes: the reactions shown for compounds ( l o ) , (13), and (14) provide further examples of these extraordinary transformations. The facility with which they occur is indeed striking" 'I.…”

Section: Ch2c1mentioning

confidence: 99%

Substitution Reactions Which Proceed via Radical Anion Intermediates

Kornblum

1975

Angew. Chem. Int. Ed. Engl.

329

104

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A new type of substitution process at a saturated carbon atom is described. These reactions, which proceed via a chain sequence in which radical anions and free radicals are intermediates, are noteworthy for providing novel and powerful means of synthesis: they occur readily under mild conditions, they give excellent yields of pure products, and, in contrast to SN2 displacements, they are rather insensitive to steric hindrance. As a consequence, radical anion processes are especially valuable for the preparation of highly branched structures. Many inorganic and organic anions readily enter into these displacements and, indeed, amines are also effective. Systems which undergo substitution via this electron transfer mechanism include benzylic, cumylic, strictly aliphatic, and heterocyclic molecules. It is of interest that a number of groups which do not behave as leaving groups in S,2 displacements are readily displaced at room temperature from a saturated carbon atom uia the radical anion-free radical pathway, e.g., nitro, azide, sulfone, and ether groups.

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Section: Ch2c1mentioning

confidence: 99%

Substitution Reactions Which Proceed via Radical Anion Intermediates

Kornblum

1975

Angew. Chem. Int. Ed. Engl.

329

104

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“…p -Nitro- α -nitrocumene, 1c. This derivative was obtained from α-bromo- p -nitrocumene (itself prepared by reaction of p -nitrocumene with N -bromosuccinimide) and sodium cyanide in DMF at 25 °C for 48 h following Kornblum's method . The product was recrystallized twice from methanol, mp 66.5−68 °C; 1 H NMR (CDCl 3 ) δ (ppm) 2.0 (s, 6H), 7.6 (d, 2H), 8.2 (d, 2H).…”

Section: Methodsmentioning

confidence: 99%

Cleavage Reactions of Radical Anions that Range from Homolytic to Heterolytic within the Same Family of Compounds

et al. 1999

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Properties of the radical anions of three R-nitrocumenes (R-nitrocumene, p-cyano-R-nitrocumene, and p-nitro-R-nitrocumene, 1a-c) have been determined by electrochemical methods. In particular, the standard potentials of the neutral/radical anion couples were found to be -2.20, -2.04, and -1.43 V with respect to the ferrocenium ion/ferrocene potential and the rate constants for expulsion of nitrite from the radical anions were 3 × 10 6 , 5 × 10 6 , and 240 s -1 for 1a-c, respectively. Comparison of these potentials with those of related compounds demonstrates that reduction of the nitroalkyl portion of the molecule occurs in 1a and 1b while in 1c the electron is added to the nitrophenyl group. Thus, using previously defined terminology, the cleavage of the radical anions of 1a and 1b to give nitrite and the corresponding cumyl radicals are examples of homolytic cleavage reactions but the cleavage of the radical anion of 1c is heterolytic. The driving force for the three cleavage reactions has been estimated and it is concluded that the large decrease in magnitude of the cleavage rate constants on going from 1a and 1b to 1c is mainly due to the much larger driving force for the first two.

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“…Kornblum’s work on nucleophilic substitution in alkyl halides [ 134 – 137 ] and Bunnett’s reactions with non-activated aromatic substrates [ 138 – 142 ] (under UV irradiation) introduced the concept of the nucleophilic radical substitution mechanism (S RN 1). The essence of this approach consists of the generation of the anionic radical RHlg −• , its decomposition to a radical R • (Alk • or Ar • ) followed by reaction with a nucleophile.…”

Section: Reviewmentioning

confidence: 99%

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

Boiko¹

2010

Beilstein J. Org. Chem.

260

119

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SummaryThis review covers all of the common methods for the syntheses of aromatic and heterocyclic perfluoroalkyl sulfides, a class of compounds which is finding increasing application as starting materials for the preparation of agrochemicals, pharmaceutical products and, more generally, fine chemicals. A systematic approach is taken depending on the mode of incorporation of the SRF groups and also on the type of reagents used.

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New and Facile Substitution Reactions at Tertiary Carbon

Cited by 45 publications

References 0 publications

Substitution Reactions Which Proceed via Radical Anion Intermediates

Substitution Reactions Which Proceed via Radical Anion Intermediates

Cleavage Reactions of Radical Anions that Range from Homolytic to Heterolytic within the Same Family of Compounds

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

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