Pyridines from Azabicyclo[3.2.0]-hept-2-en-4-ones through a Proposed Azacyclopentadienone

作者：Hemming Karl^*; Khan Musharraf N; Kondakal Vishnu V R; Pitard Arnaud; Qamar M Ilyas; Rice Craig R

来源：Organic Letters, 2012, 14(1): 126-129.

DOI：10.1021/ol202924s

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.

• 出版日期2012-1-6