Modellreaktionen zur Bildung und Öffnung von Furanen nebeneinander unter Verwendung von Diazocarbonyl-Verbindungen

Abstract

In a photochemical decomposition reaction of the a-Diazoketone 1 in the presence of toluene ring-opening of the adjacent furanoyl substituent occurs as well as conversion of a norcaradiene intermediate thus forming the acetylenic olefinic aldehyde 4 and the dihydrobenzofuran 3. Reaction pathways are derived from the corresponding ketocarbeneoxirene equilibrium in which surprisingly the secondary ketocarbene B-1 gives rise to the formation of the aldehyde 4! No Wolff rearrangement product could be detected.