ChemInform Abstract: Thiols as Polarity Reversal Catalysts for Hydrogen-Atom Transfer from Organosilanes to Alkyl Radicals: Reduction of Alkyl Halides by Triethylsilane.

ChemInform ◽  
1990 ◽  
Vol 21 (14) ◽  
Author(s):  
R. P. ALLEN ◽  
B. P. ROBERTS ◽  
C. R. WILLIS
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Atom Transfer ◽  
Alkyl Halides ◽  
Polarity Reversal ◽  
Atom Transfer ◽  
Alkyl Radicals

scholarly journals Titanium and Cobalt Bimetallic Radical Redox Relay for the Isomerization of N-Bz Aziridines to Allylic Amides

Synthesis ◽  
2021 ◽  
Author(s):  
Song Lin ◽  
Devin P. Wood ◽  
Weiyang Guan
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Atom Transfer ◽  
Alternative Strategy ◽  
Atom Transfer ◽  
Allylic Amination ◽  
Alkyl Radicals ◽  
Mild Conditions

AbstractHerein a bimetallic radical redox-relay strategy is employed to generate alkyl radicals under mild conditions with titanium(III) catalysis and terminated via hydrogen atom transfer with cobalt(II) catalysis to enact base-free isomerizations of N-Bz aziridines to N-Bz allylic amides. This reaction provides an alternative strategy for the synthesis of allylic amides from alkenes via a three-step sequence to accomplish a formal transpositional allylic amination.

Hydroalkylation of Olefins to form Quaternary Carbons

2019 ◽  
Author(s):  
Samantha Green ◽  
Tucker R. Huffman ◽  
Ruairí McCourt ◽  
Vincent van der Puyl ◽  
Ryan Shenvi
Keyword(s):  
Hydrogen Atom ◽  
Catalytic System ◽  
Metal Hydride ◽  
Hydrogen Atom Transfer ◽  
Alkyl Halides ◽  
Atom Transfer ◽  
Hydride Hydrogen ◽  
Radical Traps ◽  
Quaternary Carbons

Metal-hydride hydrogen atom transfer (MHAT) functionalizes unbiased alkenes with predictable branched (Markovnikov) selectivity. The breadth of these transformations has been confined to π-radical traps; no sp<sup>3 </sup>electrophiles have been reported. Here we describe a Mn/Ni dual catalytic system that allows for the hydroalkylation of unactivated olefins by unactivated alkyl halides, yielding aliphatic quaternary carbons.

Iminyl radicals in gas-phase synthesis. II. Formation of a-branched nitriles from cycloalkanone azines

1976 ◽  
Vol 29 (10) ◽  
pp. 2289 ◽  
Author(s):  
WD Crow ◽  
AN Khan
Keyword(s):  
Hydrogen Atom ◽  
Gas Phase ◽  
Hydrogen Atom Transfer ◽  
Ring Cleavage ◽  
Atom Transfer ◽  
Phase Synthesis ◽  
Alkyl Radicals ◽  
Gas Phase Synthesis ◽  
Internal Hydrogen

Gas-phase pyrolysis of cyclopentanone and cyclohexanone azines results in the formation of iminyl radicals. These undergo ring cleavage to the ω-cyanoalkyl radicals, which stabilize, by internal hydrogen-atom transfer, to the corresponding α-cyanoalkyl radicals. Fragmentation of the latter yields acrylonitrile and alkyl radicals, which can recombine with the α-cyanoalkyl radicals to form α-alkylated nitriles. The mechanisms involved are discussed with reference to isotopic labellingstudies.

Hydroalkylation of Olefins to form Quaternary Carbons

2019 ◽  
Author(s):  
Samantha Green ◽  
Tucker R. Huffman ◽  
Ruairí McCourt ◽  
Vincent van der Puyl ◽  
Ryan Shenvi
Keyword(s):  
Hydrogen Atom ◽  
Catalytic System ◽  
Metal Hydride ◽  
Hydrogen Atom Transfer ◽  
Alkyl Halides ◽  
Atom Transfer ◽  
Hydride Hydrogen ◽  
Radical Traps ◽  
Quaternary Carbons

Metal-hydride hydrogen atom transfer (MHAT) functionalizes unbiased alkenes with predictable branched (Markovnikov) selectivity. The breadth of these transformations has been confined to π-radical traps; no sp<sup>3 </sup>electrophiles have been reported. Here we describe a Mn/Ni dual catalytic system that allows for the hydroalkylation of unactivated olefins by unactivated alkyl halides, yielding aliphatic quaternary carbons.

Reactions of alkoxy radicals. IV. Intramolecular hydrogen-atom transfer in the presence of cupric ion: A novel directive effect

1964 ◽  
Vol 17 (12) ◽  
pp. 1342 ◽  
Author(s):  
B Acott ◽  
ALJ Beckwith
Keyword(s):  
Hydrogen Atom ◽  
Metal Ion ◽  
Hydrogen Atom Transfer ◽  
Ferrous Ion ◽  
Atom Transfer ◽  
Unsaturated Alcohol ◽  
Alkoxy Radicals ◽  
Alkyl Radicals ◽  
Cupric Ion ◽  
Intramolecular Hydrogen

2-Methyl-2-hexyloxy radical (V), generated by ferrous-ion reduction of 2-methyl-2-hexyl hydroperoxide, undergoes intramolecular hydrogen-atom transfer to the extent of 44%, yielding 2-hydroxy-2-methyl-5-hexyl radical (XIII). Oxidation of the latter with cupric ion in acetic acid affords a mixture of 2-methyl-4-hexen-2-ol (XXI) and 2-methyl-5-hexen-2-ol (XX). Similar results were obtained using radicals derived from 2,5-dimethyl-2-hexyl hydroperoxide and 2-methyl-2-heptyl hydroperoxide. In each case the preponderant formation of the unsaturated alcohol having an olefinic link in the δ-position with respect to the hydroxy group demonstrates the operation of a novel directive effect, for which a possible mechanism is discussed. Some other examples of metal-ion oxidation of alkyl radicals are described. No product arising from intramolecular hydrogen-atom transfer was isolated from ferrous-ion reduction of 2,4,4-trimethyl-2-pentyl hydroperoxide.

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