5209-25-6Relevant academic research and scientific papers
Manganese(III)-Mediated Oxidative Radical Cyclization 2. Reaction of 1,1,ω,ω-Tetraarylsubstituted Terminal Alkadienes with Malonamide or Acetoacetamide
Nishino, Hiroshi,Hashimoto, Hideaki,Korp, James D.,Kurosawa, Kazu
, p. 1999 - 2010 (1995)
The oxidation of 1,1,6,6-tetraaryl-1,5-hexadienes with manganese(III) acetate in the presence of malonamide gave two types of 5-exo cyclization products, 1-carbamoyl-8-diarylmethylene-3-azabicyclooctan-2-ones and 3,10-dioxatricyclo1,5>undecane-2,11-diones, in good to moderate yields.Similar reactions of 1,1,5,5-tetraaryl-1,4-pentadienes or 1,1,7,7-tetraaryl-1,6-heptadienes with malonamide yielded only complex mixtures, except for the formation of a small amount of 3,11-dioxatricyclo1,5>dodecane-2,12-dione.On the other hand, 1,1,5,5-tetraaryl-1,4-pentadienes reacted with acetoacetamide in the presence of manganese(III) acetate to afford 3-carbamoyl-2-methyl-4-(2-propenyl)-4,5-dihydrofurans and 1,4-pentadienes substituted at the 3-position with acetoacetamide.A similar reaction of 1,1,6,6-tetraaryl-1,5-hexadienes with acetoacetamide gave 8--3-oxabicyclooctan-2-ones, 1-acetyl-8-diarylmethylene-3-azabicyclooctan-2-ones, and 4-(3-butenyl)-3-carbamoyl-2-methyl-4,5-dihydrofurans.The selectivity of the inter- and intramolecular cyclizations containing the carboxamide moiety of malonamide or acetoacetamide is discussed.
Regioselectivity of the tri-π-methane rearrangement: Mechanistic and exploratory organic photochemistry
Zimmerman, Howard E.,Novak, Tibor
, p. 5056 - 5066 (2007/10/03)
The di-π-methane rearrangement with two π-groups attached to the central "methane carbon" of the reactant and which leads to a π-substituted cyclopropane has been studied intensively. Our present research had the goal of elucidating the regioselectivity of the tri-π-methane counterpart. The reactants with three π groups attached to the central carbon mechanistically are capable of affording both di-π-methane and tri-π-methane photoproducts. In common with the di-π-methane system, bridging of two of the π-systems affords a cyclopropyldicarbinyl diradical intermediate that opens to an allyl carbinyl diradical. This diradical has the option of closing to a three-membered or a five-membered ring. It was found that the regioselectivity of the initial π-π-bridging step and the three-ring opening of the cyclopropyldicarbinyl diradical exhibit regioselectivity parallel to that of the di-π counterpart. Both three-ring and five-ring photoproducts were formed with the ratio varying with conversion. Since the three-ring (i.e. di-π-methane) photoproducts were found to ring expand to the five-ring (i.e. tri-π-methane) products, kinetics were employed to determine to what extent the reaction proceeds in a two-step versus direct formation of the five-ring product. It was found that the direct route was the major one.
