139334-68-2Relevant academic research and scientific papers
Carbene transfer - A new pathway for propargylic esters in gold catalysis
Lauterbach, Tobias,Gatzweiler, Sabrina,Noesel, Pascal,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
, p. 2481 - 2487 (2013)
Gold (homepage: http://www.hashmi.de) carbenes generated via 1,2-migration of a propargylic ester group can be transferred over a tethered alkyne. The use of aromatic backbones leads after a 1,7-carbene transfer to a benzyl-stabilized carbene as intermediate. A 1,2-shift of a methyl group delivers vinyl-substituted β-naphthol derivatives as the final products. Copyright
Gold catalysis: β-ketonaphthalenes via molecular gymnastics of 1,6-diyne-4-en-3-ols
Lauterbach, Tobias,Arndt, Sebastian,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 1755 - 1761 (2013/07/11)
1,6-Diyne-4-en-3-ols with one terminal alkyne were applied as test substrates for a possible dual catalyzed cyclization. Instead of a dual catalysis cycle, naphthyl ketone derivatives were obtained as single products. The regioselectivity of the obtained products is unprecedented. Instead of the expected naphthyl ketones bearing the keto group in the α-position, the keto group is positioned in the ss-position of the naphthyl skeleton by a complex rearrangement of the starting materials. Copyright
A Novel Route to Isoannulated Hetereoaromatic Compounds, 2. - The Dipole Route to Furo/Thieno Pyrroles and α-Pyridones, and Their Benzo Derivatives
Bussenius, Joerg,Laber, Norbert,Mueller, Thomas,Eberbach, Wolfgang
, p. 247 - 260 (2007/10/02)
A new methodology involving 1,7-dipolar cyclizations of conjugated dipoles followed by a multistep rearrangement affording ring-contracted products has been employed for the synthesis of various examples of the title compounds.Under different thermolysis conditions the annulated alkynyl nitrones 15-19, 45, and 46 are converted into isoannulated pyrroles and α-pyridones, respectively, with yields up to 90percent (general reaction A --> B + C).The product distribution is strongly influenced by the nature of the thermal substituent R, hence supporting a mechanism with oxo carbenes as central intermediates which undergo either 6-? cyclization to the pyrrole systems or Wolff rearrangement leading to conjugated ketenes, the precursors of the observed α-pyridones (see Scheme 1).Diels-Alder reactions were performed with benzofuropyridone 40a, naphthopyridone 62 as well as with the corresponding dihydronaphtho compounds 64a, b.Whereas the tert-butyl derivatives 22b, 23b and 41b are rather unreactive against dienophiles, they are easily transformed into the cyclic imides 31, 32 and 52, respectively, under the influence of oxygen anf light suggesting the formation and subsequent cycloaddition of 1O2 as important steps. - Key Words: Pyrroles, heteroannulated / α-Pyridones, heteroannulated / Pentalenes, dihetero- / Nitrones / Heterocyclizations, 1,7-dipolar / Diels-Alder reactions / Singlet oxygen
