Unusual manganese(III)-mediated oxidative free radical additions of 1,3-dicarbonyl compounds to benzonorbornadiene and 7-heterobenzonorbornadienes: Mechanistic studies

Caliskan R. , Ali M. F. , Sahin E., Watson W. H. , Balci M.

JOURNAL OF ORGANIC CHEMISTRY, vol.72, no.9, pp.3353-3359, 2007 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 72 Issue: 9
  • Publication Date: 2007
  • Doi Number: 10.1021/jo0625711
  • Page Numbers: pp.3353-3359


Benzonorbornadiene and heterobenzonorbornadiene were reacted with dimedone/acetylacetone and Mn(OAc)(3) in the presence and absence of Cu(OAc)(2). The reaction of benzonorbornadiene with dimedone gave mainly the dihydrofuran addition product, whereas the reaction with acetylacetone produced a rearranged product in addition to the dihydrofuran derivative. On the other hand, oxanorbornadiene gave unusual products such as the cycloproponated compound and a product arising from the incorporation of 2 mol of dimedone. The reaction of azanorbornadiene with 1,3-dicarbonyl compounds and Mn(OAc)(3) always produced rearranged products. The mechanism of formation of the products is discussed. We generally observe that the cyclization reaction takes place after the oxidation of the initially formed radical.