REACTIVITY OF UNSATURATED SUBSTRATES UNDER REDUCTIVE ELECTRON-TRANSFER CONDITIONS .1. REDUCTION OF 1,2,3-TRIPHENYL-1H-INDENE WITH SODIUMMETAL IN VARIOUS SOLVENTS

Citation
S. Gotta et al., REACTIVITY OF UNSATURATED SUBSTRATES UNDER REDUCTIVE ELECTRON-TRANSFER CONDITIONS .1. REDUCTION OF 1,2,3-TRIPHENYL-1H-INDENE WITH SODIUMMETAL IN VARIOUS SOLVENTS, Perkin transactions. 2, (1), 1994, pp. 151-155
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry Physical","Chemistry Inorganic & Nuclear
Journal title
ISSN journal
0300-9580
Issue
1
Year of publication
1994
Pages
151 - 155
Database
ISI
SICI code
0300-9580(1994):1<151:ROUSUR>2.0.ZU;2-G
Abstract
The reduction of 1,2,3-triphenyl-1H-indene 1 with sodium metal in vari ous solvents was carried out in order to compare the results with thos e previously obtained in the electrochemical reduction of 1 (Hg cathod e, dimethylformamide, Bu4N+ClO4- as supporting electrolyte). The most general reaction observed was reduction of the double bond of the pent atomic cycle to afford the corresponding indanes of different configur ations. In two cases (1,2-dimethoxyethane, dioxane) this reaction was accompanied by reduction of the C(1)-H bond of 1 with formation of the corresponding anion and hydrogen. No rearrangement or cleavage of gro ups was observed. In a protic solvent (pentan-1-ol) the results are co nsistent with a reduction process occurring via protonation of the rad ical anion of 1, affording quantitatively the isomeric indanes with a slight preference for those of cis-configuration around the C(2)-C(3) bond. In liquid ammonia, in contrast, the results are indicative of a reduction process occurring via protonation of dianionic species, lead ing to the almost exclusive formation of indanes of trans-configuratio n around the C(2)-C(3) bond. The self-protonation reaction, which is t he characteristic process of reduction of 1 under electrochemical cond itions in the absence of specific proton donors, was found to be follo wed only in the case of tetrahydrofuran, where a pseudo-unimolecular d ecay of a paramagnetic species, likely the radical anion of 1, could b e followed in an EPR cavity.