33930-85-7Relevant academic research and scientific papers
Gold(I)-Catalyzed Synthesis of Indenes and Cyclopentadienes: Access to (±)-Laurokamurene B and the Skeletons of the Cycloaurenones and Dysiherbols
Yin, Xiang,Mato, Mauro,Echavarren, Antonio M.
supporting information, p. 14591 - 14595 (2017/10/18)
The formal (3+2) cycloaddition between terminal allenes and aryl or styryl gold(I) carbenes generated by a retro-Buchner reaction of 7-substituted 1,3,5-cycloheptatrienes led to indenes and cyclopentadienes, respectively. These cycloaddition processes have been applied to the construction of the carbon skeleton of the cycloaurenones and the dysiherbols as well as to the total synthesis of (±)-laurokamurene B.
15. Photochemische Reaktionen. Zur Photochemie tetraalkylsubstituierter γ-Keto-olefine
Berger, Jacob,Yoshioka, Michikazu,Zink, Markus P.,Wolf, Hans R.,Jeger, Oskar
, p. 154 - 190 (2007/10/02)
The phtochemistry of 7,8-dihydro-β-ionone (1) in solution is shown to depend on temperature, polarity and viscosity of the solvent.UV irradiation (λ>=245nm) in pentane at +25 deg converts 1 to the isomeric ethers 3 (16percent), 5A (48percent) and 5B (22percent), whereas at -65 deg 7,8-dihydro-γ-ionone (26) is obtained in 12percent yield together with 13percent of 3, 12percent of 5A and 9percent of 5B.The 1n, ?*-excitation of 1 in acetonitrile gives similar results.In the more viscous 1,2,3-triacetoxypropane the photoisomerization 1 - 26 takes place even at +60 deg (10percent yield, cf. 40percent at -15 deg).In alcoholic solvents, however, no formation of 26 is detected, but the hitherto unknown -photocycloaddition 1 - 11 can be observed (4percent at -7 deg, 15percent at -65 deg in 2-propanol).An intermediate e may be involved (Scheme 14).In addition to the photoreactions 1 - 3, 5A, 5B and 11 the isomerization of 1 to the novel spirocyclic ketone 28 takes place in alcoholic solvents only.Photoisomerization 1 - 3 is presumably a photo-ene process involving a stereoselective intramolecular H-transfer.This type of photoisomerization is restricted to cyclic γ-keto-olefines.The tetraalkylated acyclic γ-keto-olefines 14 and 15 photoisomerize exclusively by -cycloaddition, independent of the solvent.On 1n, ?*-excitation the δ, ε-unsaturated bicyclic ketone 44 undergoes Norrish-Type-II photofragmentation to the diene 45 or isomerizes to the γ, δ-unsaturated ketone 17.Competition between these two reactions is strongly temperature dependent: photolysis in pentane at -72 deg yields quantitatively 45, whereas at +35 deg only 30percent of 45 and 68percent of 17 are obtained.UV irradiation of the novel spirocyclic ketone 28 gives as primary photoproduct the isomeric aldehyde 29, and in a secondary photoreaction the isomeric oxetanes 30A and 30B.Experiments with deuteriated substartes show that the isomerization of type 28 - 29 is stereocontrolled.
