117583-08-1Relevant articles and documents
Indenols, indenones and (arylcyclohexadienyl)Mn(CO)3 π-complexes from the thermally promoted reactions of alkynes with ortho-Mn(CO)4 aryl ketone, amide, ester and aldehyde derivatives
Robinson, Nicholas P.,Depree, Gary J.,De Wit, Rene W.,Main, Lyndsay,Nicholson, Brian K.
, p. 3827 - 3837 (2005)
Thermally promoted reactions of a range of alkynes with the orthomanganated acetophenone (η2-2-acetylphenyl)Mn(CO)4 generally give 1H-inden-1-ols in good yield; effects of substituents and solvent on these reactions are reported, along with the crystal structure of 1-methyl-2,3- diphenyl-1H-inden-1-ol. The corresponding orthomanganated benzophenone similarly gives the indenol with diphenylacetylene but by exception, orthomanganated 3-acetylthiophene with phenylacetylene reacts via triple alkyne insertion and cyclisation, shown by crystal structure determination of the π-complex product [(1,2,3,4,5-η)-2-(3-acetylthien-2-yl)-1,3,5- triphenylcyclohexadienyl]tricarbonylmanganese. Corresponding orthomanganated derivatives of N,N-dimethylbenzamide, methyl 3,4,5-trimethoxybenzoate and 4-dimethylaminobenzaldehyde all give indenones with diphenylacetylene, but with (excess) acetylene only the aldehyde gives an indenone, the amide and ester giving instead [(1,2,3,4,5-η)-6-arylcyclohexadienyl]Mn(CO)3 complexes. 1H NMR analysis of these complexes shows H at C6 to be on the same face of the cyclohexadienyl ring as Mn(CO)3 (endo-6-H; exo 6-aryl) as expected from three successive syn additions of alkyne at metallated carbon followed by intramolecular syn addition of alkene in the final cyclisation stage.
Ortho-Functionalization of Aromatic Ketones via Manganation. A Synthesis of Indenols
Liebeskind, Lanny S.,Gasdaska, John R.,McCallum, J. Stuart,Tremont, Samuel J.
, p. 669 - 677 (2007/10/02)
Treatment of acetophenone with PhCH2Mn(CO)5 in refluxing heptane provides (η2-2-acetylphenyl)tetracarbonylmanganese in high yield.Conversion of the manganese complex to a reactive 16-electron species by oxidative decarboxylation with Me3N-O in CH3CN, followed by reaction with an alkyne, directly yielded substituted 1-methyl-1H-inden-1-ols in very good yields.The reaction is highly regioselective for terminal, electron-rich, electron-deficient, and 1-(trimethylsilyl)-1-alkynes as well as propargylsilanes.A number of 3-substituted acetophenones and α-tetralone andbenzsuberone were ortho-manganated and then subjected to the Me3N-O induced reaction with alkynes.On the basis of the observed regiochemistry of indenol formation from unsymmetrical alkynes (the large alkyne substituent occupies the 2-position of the indenol), the insertion of the alkyne into the manganese-carbon bond of (η2-2-acetylphenyl)tetracarbonylmanganese was rationalized as controlled by steric effects, predominantly.Carboethoxyalkynes, the one exception noted to this trend, preferentially react to give indenols with the carbethoxy group in the 2-position, regardless of the other substituent on the alkyne.
