1352447-88-1Relevant articles and documents
Pyridines from azabicyclo[3.2.0]hept-2-en-4-ones through a proposed azacyclopentadienone
Hemming, Karl,Khan, Musharraf N.,Kondakal, Vishnu V. R.,Pitard, Arnaud,Qamar, M. Ilyas,Rice, Craig R.
, p. 126 - 129 (2012/02/16)
Pyridines have been formed by heating azabicyclo[3.2.0]hept-2-en-4-ones in toluene. The generation of a 3-azacyclopentadienone intermediate via a [2 + 2]-cycloreversion is proposed as the key step. A Diels-Alder reaction of a styrene, extrusion of carbon monoxide, and loss of hydrogen then gives the pyridine. The process parallels the well-known synthesis of benzenes from cyclopentadienones. The azabicyclo[3.2.0]hept-2-en-4-ones were synthesized from the reaction between readily available cyclopropenones and 1-azetines, in which the cyclopropenones behave as all-carbon 1,3-dipolar equivalents.