- REACTIONS FOLLOWING ELECTRON TRANSFER ORIGINS OF SELECTIVITY IN THE REACTION OF RADICALS WITH CARBANIONS
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The regiochemistry observed upon arylation of ambident carbanions by phenyl radicals can be readily explained by consideration of the site of greatest basicity.Thus 1,3-diphenylindenyl anion is arylated to give predominantly 1,1,3-triphenylindene despite the presumed greater stability of the intermediate leading to 1,2,3-triphenyl indene, that is, the 1,2,3-triphenylisoindene radical anion.This explanation may also account for the preference of C-alkylation rather than O-alkylation of nitrocarbanions and for the absence of O-arylation in the SRN1 arylation of enolates.The lack of reactivity of other carbanions is rationalized on thermodynamic grounds.
- Tolbert, Laren M.,Siddiqui, Shahabuddin
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- The SRN1 Photoarylation of Indenyl Anions
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Irradiation of Me2SO solutions of indenyl anion and its phenylated analogues in the presence of bromobenzene produces the higher phenylated indenes.Thus indenyl anion (1b) yields 3-phenylindene (3a), 1-phenylindenyl anion (3b) yields 1,3- and 1,1-diphenylindene, 2-phenylindenyl anion (2b) produces 2,3-diphenylindene, 1,3-diphenylindenyl anion (6b) produces 1,1,3- and 1,2,3-triphenylindene, and 1,2-diphenylindenyl anion (5b) produces 1,2,3-triphenylindene (8).In liquid ammonia and tetrahydrofuran more complex reaction pathways are observed.The regiochemistry of phenylation is attributed to radical attack at the most basic site, in accord with a previously published model.
- Tolbert, Laren M.,Siddiqui, Shahabuddin
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p. 1744 - 1751
(2007/10/02)
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- Electrochemical Reduction of Activated Carbon-Carbon Double Bonds. 1. Mechanism and Stereochemistry of the Reduction of Phenyl-Substituted Indenes
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The reduction at a Hg electrode in DMF of some phenyl-substituted indenes was carried out, with the aim of finding out possible relationships between stereochemistry and mechanism of the reaction.The two-electron two-proton reduction occured exclusively a
- Farnia, Guiseppe,Marcuzzi, Franco,Melloni, Giovanni,Sandona, Giancarlo
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p. 6503 - 6512
(2007/10/02)
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