28072-16-4Relevant academic research and scientific papers
120. Stereoselective Ring Opening of Electronically Excited Cyclohexa-2,4-dienones: Cause and Effect
Quikert, Gerhard,Scherer, Stefan,Reichert, Dietmar,Nestler, Hans-Peter,Wennemers, Helma,Ebel, Andreas,Urbahns, Klaus,Wagner, Klaus,Michaelis, Klaus-Peter,Wiech, Gerhard,Prescher, Günter,Bronstert, Bernd,Freitag, Bernd-Jürgen,Wicke, Ilka,Lisch, Dietmar,Belik, Pavel,Crecelius, Thorsten,H?rstermann, Dirk,Zimmermann, Gottfried,Bats, Jan W.,Dürner, Gerd,Rehm, Dieter
, p. 1683 - 1772 (2007/10/03)
The two conformers of a cyclohexa-2,4-dienone with different substituents at C(6) on irradiation are believed to undergo ring opening stereospecifically affording a mixture of two configurationally isomeric diene-ketenes (and descendents thereof). Exceptions are generally found for those dienones with one C and one O substituent or even with two C substituents, if one of them carries a polar group at a site able to interact through space with the ring C=O group. In these cases, only one of the two anticipated diene-ketenes (and descendents thereof) is produced. A thorough investigation of the photochemistry of a series of structurally different cyclohexa-2,4-dienones on analytical as well as on preparative scale extends our mechanistic knowledge of the various routes from diene-ketenes into a variety of compound classes. Novel compound classes accessible to diene-ketenes are seven-membered carbocycles (by intramolecular aldolization of the zwitterion of appropriately substituted, transiently formed diene-(N,O)-ketene acetals) and βlactams (by Staudinger reaction).
